diff --git a/__snapshots__/blame-spec.js b/__snapshots__/blame-spec.js
new file mode 100644
index 0000000..315d845
--- /dev/null
+++ b/__snapshots__/blame-spec.js
@@ -0,0 +1,724 @@
+exports['blame mocks exec and parses output 1'] = {
+  "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+  "author": "Gleb Bahmutov",
+  "committer": "Gleb Bahmutov",
+  "summary": "mock commit",
+  "filename": "spec/blame-spec.js",
+  "line": "this is mock line 10000"
+}
+
+exports['blame can grab blame for entire file 1'] = [
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst la = require('lazy-ass')"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst is = require('check-more-types')"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst schemaShot = require('schema-shot')"
+  },
+  {
+    "commit": "9a86d902bc83cadc69f27e012ad7e6c3203ac388",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "start work on commit message for any commit",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst snapshot = require('snap-shot-it')"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst { stubExecOnce } = require('stub-spawn-once')"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst { stripIndent } = require('common-tags')"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "ca3bf0d54fa3e0782e252e67cc14390a52f3f784",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "restore file system before loading snapshot",
+    "filename": "spec/blame-spec.js",
+    "line": "\t/* global describe, it, beforeEach */"
+  },
+  {
+    "commit": "a24a1255531ea46f0b721661fac847a5fe6009f9",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "test blame entire file",
+    "filename": "spec/blame-spec.js",
+    "line": "\tdescribe('blame', () => {"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  const blame = require('..').blame"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  it('is a function', () => {"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    la(is.fn(blame))"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  })"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  it('gets blame for 1 line of this file', () => {"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const line = 1"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    return schemaShot(blame(__filename, line))"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  })"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  it('mocks exec and parses output', () => {"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    // line 10000 does NOT exist in this file!"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const line = 10000"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const cmd = `git blame --porcelain -L ${line},${line} ${__filename}`"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const output = stripIndent`"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      adfb30d5888bb1eb9bad1f482248edec2947dab6 ${line} ${line} 1"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      author Gleb Bahmutov"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      author-mail <gleb.bahmutov@gmail.com>"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      author-time 1499944626"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      author-tz -0400"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      committer Gleb Bahmutov"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      committer-mail <gleb.bahmutov@gmail.com>"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      committer-time 1499944626"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      committer-tz -0400"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      summary mock commit"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      filename spec/blame-spec.js"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      this is mock line ${line}"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    `"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    stubExecOnce(cmd, output)"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    // can use exact snapshot here, because the output will always be"
+  },
+  {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    // the same! See __snapshots__/blame-spec.js.snap-shot"
+  },
+  {
+    "commit": "0000000000000000000000000000000000000000",
+    "author": "Not Committed Yet",
+    "committer": "Not Committed Yet",
+    "summary": "Version of spec/blame-spec.js from spec/blame-spec.js",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    return blame(__filename, line).then(snapshot)"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  })"
+  },
+  {
+    "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "move blame test",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "a24a1255531ea46f0b721661fac847a5fe6009f9",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "test blame entire file",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  it('can grab blame for entire file', () => {"
+  },
+  {
+    "commit": "0000000000000000000000000000000000000000",
+    "author": "Not Committed Yet",
+    "committer": "Not Committed Yet",
+    "summary": "Version of spec/blame-spec.js from spec/blame-spec.js",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    return blame(__filename).then(snapshot)"
+  },
+  {
+    "commit": "a24a1255531ea46f0b721661fac847a5fe6009f9",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "test blame entire file",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  })"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  describe('non-existent file', () => {"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const fs = require('fs')"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const sinon = require('sinon')"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const path = require('path')"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const line = 42"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const file = 'foo.txt'"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    const fullFilename = path.resolve(file)"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    beforeEach(() => {"
+  },
+  {
+    "commit": "78bf5f3a009f0cab9a176e66e9d81e13feb25a40",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "upgrade deps",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      sinon"
+  },
+  {
+    "commit": "78bf5f3a009f0cab9a176e66e9d81e13feb25a40",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "upgrade deps",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        .stub(fs, 'existsSync')"
+  },
+  {
+    "commit": "78bf5f3a009f0cab9a176e66e9d81e13feb25a40",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "upgrade deps",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        .withArgs(file)"
+  },
+  {
+    "commit": "78bf5f3a009f0cab9a176e66e9d81e13feb25a40",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "upgrade deps",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        .returns(true)"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      const cmd = `git blame --porcelain -L ${line},${line} ${fullFilename}`"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      const output = stripIndent`"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        adfb30d5888bb1eb9bad1f482248edec2947dab6 ${line} ${line} 1"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        author Gleb Bahmutov"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        author-mail <gleb.bahmutov@gmail.com>"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        author-time 1499944626"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        author-tz -0400"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        committer Gleb Bahmutov"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        committer-mail <gleb.bahmutov@gmail.com>"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        committer-time 1499944626"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        committer-tz -0400"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        summary mock commit"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        filename spec/blame-spec.js"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t        this is mock line ${line}"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      `"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      stubExecOnce(cmd, output)"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    })"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    it('can mock blame for non-existent file', () => {"
+  },
+  {
+    "commit": "ca3bf0d54fa3e0782e252e67cc14390a52f3f784",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "restore file system before loading snapshot",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      const result = blame(file, line)"
+  },
+  {
+    "commit": "ca3bf0d54fa3e0782e252e67cc14390a52f3f784",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "restore file system before loading snapshot",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      // restore file system in order for snapshots to load"
+  },
+  {
+    "commit": "ca3bf0d54fa3e0782e252e67cc14390a52f3f784",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "restore file system before loading snapshot",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      fs.existsSync.restore()"
+  },
+  {
+    "commit": "ca3bf0d54fa3e0782e252e67cc14390a52f3f784",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "restore file system before loading snapshot",
+    "filename": "spec/blame-spec.js",
+    "line": "\t      return snapshot(result)"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t    })"
+  },
+  {
+    "commit": "159c3764365be53f9894db6b55aa6dd4dbffd4de",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mocking blame",
+    "filename": "spec/blame-spec.js",
+    "line": "\t  })"
+  },
+  {
+    "commit": "a24a1255531ea46f0b721661fac847a5fe6009f9",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "test blame entire file",
+    "filename": "spec/blame-spec.js",
+    "line": "\t})"
+  }
+]
+
+exports['blame non-existent file can mock blame for non-existent file 1'] = {
+  "commit": "adfb30d5888bb1eb9bad1f482248edec2947dab6",
+  "author": "Gleb Bahmutov",
+  "committer": "Gleb Bahmutov",
+  "summary": "mock commit",
+  "filename": "spec/blame-spec.js",
+  "line": "this is mock line 42"
+}
diff --git a/__snapshots__/blame-spec.js.schema-shot b/__snapshots__/blame-spec.js.schema-shot
new file mode 100644
index 0000000..5b9e370
--- /dev/null
+++ b/__snapshots__/blame-spec.js.schema-shot
@@ -0,0 +1,82 @@
+exports['gets blame for 1 line of this file 1'] = {
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": "object",
+  "properties": {
+    "commit": {
+      "type": "string",
+      "required": true
+    },
+    "author": {
+      "type": "string",
+      "required": true
+    },
+    "committer": {
+      "type": "string",
+      "required": true
+    },
+    "summary": {
+      "type": "string",
+      "required": true
+    },
+    "filename": {
+      "type": "string",
+      "required": true
+    },
+    "line": {
+      "type": "string",
+      "required": true
+    }
+  },
+  "additionalProperties": false,
+  "list": false,
+  "example": {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst la = require('lazy-ass')"
+  }
+}
+
+exports['can grab blame for entire file 1'] = {
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": "object",
+  "properties": {
+    "commit": {
+      "type": "string",
+      "required": true
+    },
+    "author": {
+      "type": "string",
+      "required": true
+    },
+    "committer": {
+      "type": "string",
+      "required": true
+    },
+    "summary": {
+      "type": "string",
+      "required": true
+    },
+    "filename": {
+      "type": "string",
+      "required": true
+    },
+    "line": {
+      "type": "string",
+      "required": true
+    }
+  },
+  "additionalProperties": false,
+  "list": true,
+  "example": {
+    "commit": "b2bf285c40b0c17743d84495b69c51d4c6367089",
+    "author": "Gleb Bahmutov",
+    "committer": "Gleb Bahmutov",
+    "summary": "mock test",
+    "filename": "spec/blame-spec.js",
+    "line": "\tconst la = require('lazy-ass')"
+  }
+}
+
diff --git a/__snapshots__/commit-numstat-utils-spec.js b/__snapshots__/commit-numstat-utils-spec.js
new file mode 100644
index 0000000..d565661
--- /dev/null
+++ b/__snapshots__/commit-numstat-utils-spec.js
@@ -0,0 +1,13 @@
+exports['parsing commit numstat regular commit 1'] = {
+  "commit": "0b3342816ac2db82d051233e884ff93ddb811b17",
+  "author": "Renovate Bot <bot@renovateapp.com>",
+  "date": "Sat Dec 22 22:15:32 2018 +0000",
+  "message": "chore(deps): update dependency mocked-env to v1.2.4"
+}
+
+exports['parsing commit numstat merged commit 1'] = {
+  "commit": "f2d8d7f2b2de0df9cfc14845d284521eb2513c0c",
+  "author": "Gleb Bahmutov <gleb.bahmutov@gmail.com>",
+  "date": "Fri Aug 9 10:59:17 2019 -0400",
+  "message": "fix: update lodash"
+}
diff --git a/__snapshots__/commits-spec.js b/__snapshots__/commits-spec.js
new file mode 100644
index 0000000..a57ae7a
--- /dev/null
+++ b/__snapshots__/commits-spec.js
@@ -0,0 +1,12 @@
+exports['commits all parses given output 1'] = [
+  {
+    "id": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    "message": "first commit",
+    "body": ""
+  },
+  {
+    "id": "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
+    "message": "second commit",
+    "body": ""
+  }
+]
diff --git a/__snapshots__/one-line-log-spec.js b/__snapshots__/one-line-log-spec.js
new file mode 100644
index 0000000..488093c
--- /dev/null
+++ b/__snapshots__/one-line-log-spec.js
@@ -0,0 +1,21 @@
+exports['one line log parses mock output 1'] = [
+  {
+    "id": "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
+    "message": "commit B"
+  },
+  {
+    "id": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    "message": "commit A"
+  }
+]
+
+exports['one line log parses mock output with branch name 1'] = [
+  {
+    "id": "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
+    "message": "commit B"
+  },
+  {
+    "id": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    "message": "commit A"
+  }
+]
diff --git a/__snapshots__/one-line-log-spec.js.schema-shot b/__snapshots__/one-line-log-spec.js.schema-shot
new file mode 100644
index 0000000..0d8b8e3
--- /dev/null
+++ b/__snapshots__/one-line-log-spec.js.schema-shot
@@ -0,0 +1,21 @@
+exports['grabs last 5 commits schema 1'] = {
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": "object",
+  "properties": {
+    "id": {
+      "type": "string",
+      "required": true
+    },
+    "message": {
+      "type": "string",
+      "required": true
+    }
+  },
+  "additionalProperties": false,
+  "list": true,
+  "example": {
+    "id": "f2d8d7f2b2de0df9cfc14845d284521eb2513c0c",
+    "message": "fix: update lodash"
+  }
+}
+
diff --git a/package-lock.json b/package-lock.json
index 0263c74..599014e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -526,6 +526,12 @@
         "readable-stream": "^2.0.6"
       }
     },
+    "arg": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/arg/-/arg-4.1.0.tgz",
+      "integrity": "sha512-ZWc51jO3qegGkVh8Hwpv636EkbesNV5ZNQPCtRa+0qytRYPEs9IYT9qITY9buezqUH5uqyzlWLcufrzU2rffdg==",
+      "dev": true
+    },
     "argparse": {
       "version": "0.1.16",
       "resolved": "https://registry.npmjs.org/argparse/-/argparse-0.1.16.tgz",
@@ -3579,9 +3585,9 @@
       "dev": true
     },
     "folktale": {
-      "version": "2.0.1",
-      "resolved": "https://registry.npmjs.org/folktale/-/folktale-2.0.1.tgz",
-      "integrity": "sha512-3kDSWVkSlErHIt/dC73vu+5zRqbW1mlnL46s2QfYN7Ps0JcS9MVtuLCrDQOBa7sanA+d9Fd8F+bn0VcyNe68Jw==",
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/folktale/-/folktale-2.3.2.tgz",
+      "integrity": "sha512-+8GbtQBwEqutP0v3uajDDoN64K2ehmHd0cjlghhxh0WpcfPzAIjPA03e1VvHlxL02FVGR0A6lwXsNQKn3H1RNQ==",
       "dev": true
     },
     "for-in": {
@@ -5646,6 +5652,12 @@
       "integrity": "sha1-JOwVr/pdADnog5aVohwsrh9Ftms=",
       "dev": true
     },
+    "its-name": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/its-name/-/its-name-1.0.0.tgz",
+      "integrity": "sha1-IGXxiD7LVoxl9xEt2/EjQB+uSvA=",
+      "dev": true
+    },
     "js-tokens": {
       "version": "3.0.2",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-3.0.2.tgz",
@@ -9096,32 +9108,48 @@
       "dev": true
     },
     "snap-shot-compare": {
-      "version": "2.7.1",
-      "resolved": "https://registry.npmjs.org/snap-shot-compare/-/snap-shot-compare-2.7.1.tgz",
-      "integrity": "sha512-qJPyYskLyuOOON1rFjO5xHmeVduaNJGd6AgeWqq8F6rVE+n79Jr7wdML2qrODoAeb63zztd5JB9Cc8WSWV/rig==",
+      "version": "2.8.3",
+      "resolved": "https://registry.npmjs.org/snap-shot-compare/-/snap-shot-compare-2.8.3.tgz",
+      "integrity": "sha512-dznYMQAYMcQ4crFduIX5sST/Ex35l414hVCL6sXFi84OPuwG5eXgRBfBqbgz7mi3rC/r7VWDn2ADF8FTV/wbCw==",
       "dev": true,
       "requires": {
         "check-more-types": "2.24.0",
+        "debug": "4.1.1",
         "disparity": "2.0.0",
-        "folktale": "2.0.1",
+        "folktale": "2.3.2",
         "lazy-ass": "1.6.0",
-        "strip-ansi": "4.0.0",
+        "strip-ansi": "5.2.0",
         "variable-diff": "1.1.0"
       },
       "dependencies": {
         "ansi-regex": {
-          "version": "3.0.0",
-          "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-3.0.0.tgz",
-          "integrity": "sha1-7QMXwyIGT3lGbAKWa922Bas32Zg=",
+          "version": "4.1.0",
+          "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-4.1.0.tgz",
+          "integrity": "sha512-1apePfXM1UOSqw0o9IiFAovVz9M5S1Dg+4TrDwfMewQ6p/rmMueb7tWZjQ1rx4Loy1ArBggoqGpfqqdI4rondg==",
+          "dev": true
+        },
+        "debug": {
+          "version": "4.1.1",
+          "resolved": "https://registry.npmjs.org/debug/-/debug-4.1.1.tgz",
+          "integrity": "sha512-pYAIzeRo8J6KPEaJ0VWOh5Pzkbw/RetuzehGM7QRRX5he4fPHx2rdKMB256ehJCkX+XRQm16eZLqLNS8RSZXZw==",
+          "dev": true,
+          "requires": {
+            "ms": "^2.1.1"
+          }
+        },
+        "ms": {
+          "version": "2.1.2",
+          "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
+          "integrity": "sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w==",
           "dev": true
         },
         "strip-ansi": {
-          "version": "4.0.0",
-          "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-4.0.0.tgz",
-          "integrity": "sha1-qEeQIusaw2iocTibY1JixQXuNo8=",
+          "version": "5.2.0",
+          "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-5.2.0.tgz",
+          "integrity": "sha512-DuRs1gKbBqsMKIZlrffwlug8MHkcnpjs5VPmL1PAh+mA30U0DTotfDZ0d2UUsXpPmPmMMJ6W773MaA3J+lbiWA==",
           "dev": true,
           "requires": {
-            "ansi-regex": "^3.0.0"
+            "ansi-regex": "^4.1.0"
           }
         }
       }
@@ -9169,25 +9197,28 @@
       }
     },
     "snap-shot-it": {
-      "version": "6.2.8",
-      "resolved": "https://registry.npmjs.org/snap-shot-it/-/snap-shot-it-6.2.8.tgz",
-      "integrity": "sha512-VJkubD1CiX7/M63zyD0cBj7EzdtM2/pMeV2t8pKfGtc8Nxm+fxYPPul0BXDrp+fLG8/7igpGe9Cnd0cs67FTgw==",
+      "version": "7.8.0",
+      "resolved": "https://registry.npmjs.org/snap-shot-it/-/snap-shot-it-7.8.0.tgz",
+      "integrity": "sha512-d83qtfNdlYogDF/fti8ya12P1WT/iBRcbHl3IYpIoUtFg6LP+G/QphPwF0zRDpR36SgFVqLvj9XpWDceHiHkmw==",
       "dev": true,
       "requires": {
         "@bahmutov/data-driven": "1.0.0",
         "check-more-types": "2.24.0",
+        "common-tags": "1.8.0",
         "debug": "4.1.1",
         "has-only": "1.1.1",
-        "pluralize": "7.0.0",
+        "its-name": "1.0.0",
+        "lazy-ass": "1.6.0",
+        "pluralize": "8.0.0",
         "ramda": "0.26.1",
-        "snap-shot-compare": "2.7.1",
-        "snap-shot-core": "7.1.11"
+        "snap-shot-compare": "2.8.3",
+        "snap-shot-core": "10.1.1"
       },
       "dependencies": {
         "ci-info": {
-          "version": "1.6.0",
-          "resolved": "https://registry.npmjs.org/ci-info/-/ci-info-1.6.0.tgz",
-          "integrity": "sha512-vsGdkwSCDpWmP80ncATX7iea5DWQemg1UgCW5J8tqjU3lYw4FBYuj89J0CTVomA7BEfvSZd84GmHko+MxFQU2A==",
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/ci-info/-/ci-info-2.0.0.tgz",
+          "integrity": "sha512-5tK7EtrZ0N+OLFMthtqOj4fI2Jeb88C4CAZPu25LDVUgXJ0A3Js4PMGqrn0JU1W0Mh1/Z8wZzYPxqUrXeBboCQ==",
           "dev": true
         },
         "debug": {
@@ -9199,19 +9230,13 @@
             "ms": "^2.1.1"
           }
         },
-        "folktale": {
-          "version": "2.3.1",
-          "resolved": "https://registry.npmjs.org/folktale/-/folktale-2.3.1.tgz",
-          "integrity": "sha512-x16IvpoFrLxOYbAC4G/ban4eWOGoREcrfaVSiTsDknrRYHMe+W4XUekCYA6w4YyjQpcL8nsNt4A5EUUKjFSpRg==",
-          "dev": true
-        },
         "is-ci": {
-          "version": "1.2.1",
-          "resolved": "https://registry.npmjs.org/is-ci/-/is-ci-1.2.1.tgz",
-          "integrity": "sha512-s6tfsaQaQi3JNciBH6shVqEDvhGut0SUXr31ag8Pd8BBbVVlcGfWhpPmEOoM6RJ5TFhbypvf5yyRw/VXW1IiWg==",
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/is-ci/-/is-ci-2.0.0.tgz",
+          "integrity": "sha512-YfJT7rkpQB0updsdHLGWrvhBJfcfzNNawYDNIyQXJz0IViGf75O8EBPKSdvw2rF+LGCsX4FZ8tcr3b19LcZq4w==",
           "dev": true,
           "requires": {
-            "ci-info": "^1.5.0"
+            "ci-info": "^2.0.0"
           }
         },
         "jsesc": {
@@ -9221,45 +9246,36 @@
           "dev": true
         },
         "ms": {
-          "version": "2.1.1",
-          "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.1.tgz",
-          "integrity": "sha512-tgp+dl5cGk28utYktBsrFqA7HKgrhgPsg6Z/EfhWI4gl1Hwq8B/GmY/0oXZ6nF8hDVesS/FpnYaD/kOWhYQvyg==",
+          "version": "2.1.2",
+          "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
+          "integrity": "sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w==",
           "dev": true
         },
-        "ramda": {
-          "version": "0.26.1",
-          "resolved": "https://registry.npmjs.org/ramda/-/ramda-0.26.1.tgz",
-          "integrity": "sha512-hLWjpy7EnsDBb0p+Z3B7rPi3GDeRG5ZtiI33kJhTt+ORCd38AbAIjB/9zRIUoeTbE/AVX5ZkU7m6bznsvrf8eQ==",
+        "pluralize": {
+          "version": "8.0.0",
+          "resolved": "https://registry.npmjs.org/pluralize/-/pluralize-8.0.0.tgz",
+          "integrity": "sha512-Nc3IT5yHzflTfbjgqWcCPpo7DaKy4FnpB0l/zCAW0Tc7jxAiuqSxHasntB3D7887LSrA93kDJ9IXovxJYxyLCA==",
           "dev": true
         },
         "snap-shot-core": {
-          "version": "7.1.11",
-          "resolved": "https://registry.npmjs.org/snap-shot-core/-/snap-shot-core-7.1.11.tgz",
-          "integrity": "sha512-/USGJ0WKhMyOY6Z4FUs2wjEI01eAILcJ1bcIduZOP6l6jMu2nABvMzU/Bd2fRDrdyxXOpqhyzcZCdGJcQtDuYQ==",
+          "version": "10.1.1",
+          "resolved": "https://registry.npmjs.org/snap-shot-core/-/snap-shot-core-10.1.1.tgz",
+          "integrity": "sha512-xrltUg35pvs+d3VliYUJxe2sma45O4kenSf0i4XUoQtG6KZd/hJufu4OtlMDNCjA8cq12bgHZqy7ok/rRAwW+g==",
           "dev": true,
           "requires": {
+            "arg": "4.1.0",
             "check-more-types": "2.24.0",
             "common-tags": "1.8.0",
-            "debug": "3.2.6",
+            "debug": "4.1.1",
             "escape-quotes": "1.0.2",
-            "folktale": "2.3.1",
-            "is-ci": "1.2.1",
+            "folktale": "2.3.2",
+            "is-ci": "2.0.0",
             "jsesc": "2.5.2",
             "lazy-ass": "1.6.0",
             "mkdirp": "0.5.1",
-            "pluralize": "7.0.0",
+            "pluralize": "8.0.0",
+            "quote": "0.4.0",
             "ramda": "0.26.1"
-          },
-          "dependencies": {
-            "debug": {
-              "version": "3.2.6",
-              "resolved": "https://registry.npmjs.org/debug/-/debug-3.2.6.tgz",
-              "integrity": "sha512-mel+jf7nrtEl5Pn1Qx46zARXKDpBbvzezse7p7LqINmdoIk8PYP5SySaxEmYv6TZ0JyEKA1hsCId6DIhgITtWQ==",
-              "dev": true,
-              "requires": {
-                "ms": "^2.1.1"
-              }
-            }
           }
         }
       }
@@ -10224,7 +10240,7 @@
     },
     "text-encoding": {
       "version": "0.6.4",
-      "resolved": "http://registry.npmjs.org/text-encoding/-/text-encoding-0.6.4.tgz",
+      "resolved": "https://registry.npmjs.org/text-encoding/-/text-encoding-0.6.4.tgz",
       "integrity": "sha1-45mpgiV6J22uQou5KEXLcb3CbRk=",
       "dev": true
     },
diff --git a/package.json b/package.json
index 4721a40..360921d 100644
--- a/package.json
+++ b/package.json
@@ -80,7 +80,7 @@
     "semantic-release": "8.2.3",
     "simple-commit-message": "4.0.3",
     "sinon": "6.3.5",
-    "snap-shot-it": "6.2.8",
+    "snap-shot-it": "7.8.0",
     "standard": "11.0.1",
     "stop-only": "2.2.1",
     "stub-spawn-once": "2.3.0",
diff --git a/spec/blame-spec.js b/spec/blame-spec.js
index e883c04..a4229f8 100644
--- a/spec/blame-spec.js
+++ b/spec/blame-spec.js
@@ -4,10 +4,12 @@ const schemaShot = require('schema-shot')
 const snapshot = require('snap-shot-it')
 const { stubExecOnce } = require('stub-spawn-once')
 const { stripIndent } = require('common-tags')
+const path = require('path')
 
 /* global describe, it, beforeEach */
 describe('blame', () => {
   const blame = require('..').blame
+  const testFilename = path.join(__dirname, 'test-file.txt')
 
   it('is a function', () => {
     la(is.fn(blame))
@@ -15,13 +17,13 @@ describe('blame', () => {
 
   it('gets blame for 1 line of this file', () => {
     const line = 1
-    return schemaShot(blame(__filename, line))
+    return schemaShot(blame(testFilename, line))
   })
 
   it('mocks exec and parses output', () => {
     // line 10000 does NOT exist in this file!
     const line = 10000
-    const cmd = `git blame --porcelain -L ${line},${line} ${__filename}`
+    const cmd = `git blame --porcelain -L ${line},${line} ${testFilename}`
     const output = stripIndent`
       adfb30d5888bb1eb9bad1f482248edec2947dab6 ${line} ${line} 1
       author Gleb Bahmutov
@@ -39,11 +41,11 @@ describe('blame', () => {
     stubExecOnce(cmd, output)
     // can use exact snapshot here, because the output will always be
     // the same! See __snapshots__/blame-spec.js.snap-shot
-    return snapshot(blame(__filename, line))
+    return blame(testFilename, line).then(snapshot)
   })
 
   it('can grab blame for entire file', () => {
-    return schemaShot(blame(__filename))
+    return blame(testFilename).then(snapshot)
   })
 
   describe('non-existent file', () => {
@@ -82,7 +84,7 @@ describe('blame', () => {
       const result = blame(file, line)
       // restore file system in order for snapshots to load
       fs.existsSync.restore()
-      return snapshot(result)
+      return result.then(snapshot)
     })
   })
 })
diff --git a/spec/commits-spec.js b/spec/commits-spec.js
index 0028bd8..9b5e8c4 100644
--- a/spec/commits-spec.js
+++ b/spec/commits-spec.js
@@ -40,7 +40,7 @@ describe('commits', () => {
             second commit
         `
       )
-      return snapshot(commits.all())
+      return commits.all().then(snapshot)
     })
   })
 
diff --git a/spec/test-file.txt b/spec/test-file.txt
new file mode 100644
index 0000000..3cff583
--- /dev/null
+++ b/spec/test-file.txt
@@ -0,0 +1,4 @@
+This is a file to test getting blame for entire file or individual lines
+line 1
+line 2
+line 3
diff --git a/spec/utils-spec.js b/spec/utils-spec.js
index 3f48123..014852b 100644
--- a/spec/utils-spec.js
+++ b/spec/utils-spec.js
@@ -3,7 +3,7 @@ const is = require('check-more-types')
 const R = require('ramda')
 
 /* eslint-env mocha */
-describe.only('utils', () => {
+describe('utils', () => {
   describe('buildInfo', () => {
     const buildInfo = require('../src/utils').buildInfo
     const options = {
diff --git a/src/blame.js b/src/blame.js
index 0100be8..19d41c0 100644
--- a/src/blame.js
+++ b/src/blame.js
@@ -152,7 +152,7 @@ function blameOneLine (filename, lineNumber) {
     lineNumber +
     ' ' +
     fullFilename
-  return exec(cmd).then(toBlameInfo)
+  return exec.exec(cmd).then(toBlameInfo)
 }
 
 function blame (filename, lineNumber) {
@@ -174,7 +174,7 @@ function blame (filename, lineNumber) {
   console.log('who to blame for', fullFilename)
   // http://git-scm.com/docs/git-blame
   var cmd = 'git blame --porcelain --line-porcelain ' + fullFilename
-  return exec(cmd).then(toBlameInfoFile)
+  return exec.exec(cmd).then(toBlameInfoFile)
 }
 
 module.exports = blame
diff --git a/src/branch-name.js b/src/branch-name.js
index d8cd76d..e51d504 100644
--- a/src/branch-name.js
+++ b/src/branch-name.js
@@ -7,7 +7,7 @@ var exec = require('./exec')
 */
 function branchName () {
   var cmd = 'git rev-parse --abbrev-ref HEAD'
-  return exec(cmd).then(function cleanOutput (str) {
+  return exec.exec(cmd).then(function cleanOutput (str) {
     la(check.unemptyString(str), 'expected branch name string', str)
     return str.trim()
   })
diff --git a/src/changed-files.js b/src/changed-files.js
index 3871a61..46f373d 100644
--- a/src/changed-files.js
+++ b/src/changed-files.js
@@ -110,7 +110,7 @@ function changedFiles (needContents) {
   // another command that gives status especially for added files
   var secondCommand = 'git status --porcelain'
 
-  return Q.all([exec(cmd), exec(secondCommand)])
+  return Q.all([exec.exec(cmd), exec.exec(secondCommand)])
     .spread(function (firstOutput, secondOutput) {
       log('first output')
       log(firstOutput)
diff --git a/src/clone-repo-spec.js b/src/clone-repo-spec.js
index 634f5bf..399cec5 100644
--- a/src/clone-repo-spec.js
+++ b/src/clone-repo-spec.js
@@ -11,7 +11,7 @@ describe('clone-repo', () => {
   function removeTempFolder () {
     if (fs.existsSync(destFolder)) {
       console.log('removing folder', destFolder)
-      return exec('rm -rf ' + destFolder)
+      return exec.exec('rm -rf ' + destFolder)
     }
   }
 
diff --git a/src/clone-repo.js b/src/clone-repo.js
index 0ee873b..6ee59ad 100644
--- a/src/clone-repo.js
+++ b/src/clone-repo.js
@@ -10,7 +10,7 @@ function cloneRepo (opts) {
     throw new Error('Destination folder ' + opts.folder + ' already exists')
   }
   var cmd = 'git clone --depth 1 ' + opts.url + ' ' + opts.folder
-  return exec(cmd)
+  return exec.exec(cmd)
 }
 
 module.exports = cloneRepo
diff --git a/src/commit-message.js b/src/commit-message.js
index 057b2c1..c86ba36 100644
--- a/src/commit-message.js
+++ b/src/commit-message.js
@@ -57,7 +57,7 @@ function commitMessageFor (sha) {
   la(is.unemptyString(sha), 'expected commit sha', sha)
   debug('getting commit message for', sha)
   const cmd = 'git show --format="%ae%n%s%n%b" --no-patch ' + sha
-  return exec(cmd).then(parseCommitMessage)
+  return exec.exec(cmd).then(parseCommitMessage)
 }
 
 function commitMessage (sha) {
diff --git a/src/commit-numstat-utils-spec.js b/src/commit-numstat-utils-spec.js
new file mode 100644
index 0000000..23f03f7
--- /dev/null
+++ b/src/commit-numstat-utils-spec.js
@@ -0,0 +1,49 @@
+/* eslint-env mocha */
+const { stripIndent } = require('common-tags')
+const debug = require('debug')('test')
+const snapshot = require('snap-shot-it')
+const la = require('lazy-ass')
+
+describe('parsing commit numstat', () => {
+  const { commitMeta } = require('./commit-numstat-utils')
+
+  it('regular commit', function () {
+    // output from "git show --numstat <commit id>" command
+    const stdout = stripIndent`
+      commit 0b3342816ac2db82d051233e884ff93ddb811b17
+      Author: Renovate Bot <bot@renovateapp.com>
+      Date:   Sat Dec 22 22:15:32 2018 +0000
+
+          chore(deps): update dependency mocked-env to v1.2.4
+
+      5   22  package-lock.json
+      1   1   package.json
+    `
+    const meta = commitMeta(stdout.split('\n'))
+    debug('meta is %o', meta)
+    la(meta.message, 'has parsed message text', meta)
+    snapshot(meta)
+  })
+
+  it('merged commit', function () {
+    // output from "git show --numstat <commit id>" command
+    // for a merge commit
+    const stdout = stripIndent`
+      commit f2d8d7f2b2de0df9cfc14845d284521eb2513c0c (HEAD -> master, origin/master, origin/HEAD)
+      Merge: 4fe1eaf 884c7bd
+      Author: Gleb Bahmutov <gleb.bahmutov@gmail.com>
+      Date:   Fri Aug 9 10:59:17 2019 -0400
+
+          fix: update lodash
+
+          Update lodash
+
+      3   3   package-lock.json
+      1   1   package.json
+    `
+    const meta = commitMeta(stdout.split('\n'))
+    debug('meta is %o', meta)
+    la(meta.message, 'has parsed message text', meta)
+    snapshot(meta)
+  })
+})
diff --git a/src/commit-numstat-utils.js b/src/commit-numstat-utils.js
new file mode 100644
index 0000000..15d1e95
--- /dev/null
+++ b/src/commit-numstat-utils.js
@@ -0,0 +1,104 @@
+var la = require('lazy-ass')
+var check = require('check-more-types')
+var debug = require('debug')('ggit')
+
+/**
+ * parses date, author, message from a merge commit.
+ */
+function commitMergeMeta (lines) {
+  la(lines.length > 3, 'expected more lines', lines)
+
+  var commit = lines[0].split(' ')[1].trim()
+  var author = lines[2].split(':')[1].trim()
+  // remove Date:
+  var date = lines[3].substr(5).trim()
+  var message = lines[5].trim()
+
+  return {
+    commit: commit,
+    author: author,
+    date: date,
+    message: message
+  }
+}
+
+/**
+ * parses date, author, message from a regular or merge commit.
+ */
+function commitMeta (lines) {
+  la(lines.length > 3, 'expected more lines', lines)
+  if (lines[1].indexOf('Merge:') !== -1) {
+    return commitMergeMeta(lines)
+  }
+
+  var commit = lines[0].split(' ')[1].trim()
+  var author = lines[1].split(':')[1].trim()
+  // remove Date:
+  var date = lines[2].substr(5).trim()
+  var message = lines[4].trim()
+
+  return {
+    commit: commit,
+    author: author,
+    date: date,
+    message: message
+  }
+}
+
+/*
+parses git show --numstat output, which is something like this
+
+$ git show --numstat 46350c2
+commit 46350c2c9980551d338ce1ad0d8eff7bea9713ec
+Author: Gleb Bahmutov <gleb.bahmutov@gmail.com>
+Date:   Mon Jan 13 19:04:06 2014 -0500
+
+    better gruntfile
+
+1       1       .jshintrc
+54      25      Gruntfile.js
+9       0       complexity.json
+2       1       package.json
+*/
+function isValidLine (line) {
+  var rex = /^\s*\d+\s+\d+[\w\W]+$/
+  return line && rex.test(line)
+}
+la(isValidLine('1  1 time-method-call.js'))
+la(isValidLine(' 1  0 README.md'))
+
+function parseNumstat (stdout) {
+  la(check.unemptyString(stdout), 'missing numstat output', stdout)
+  var lines = stdout.split('\n')
+  la(lines.length > 3, 'expected more lines', stdout)
+
+  var info = commitMeta(lines)
+  debug('commit meta %o', info)
+
+  var k = 6
+  var fileChanges = {}
+  for (; k < lines.length; k += 1) {
+    if (isValidLine(lines[k])) {
+      var parts = lines[k].split('\t')
+      var added = Number(parts[0].trim())
+      var deleted = Number(parts[1].trim())
+      var filename = parts[2].trim()
+      fileChanges[filename] = {
+        filename: filename,
+        added: added,
+        deleted: deleted
+      }
+    }
+  }
+
+  debug('parsed numstat %o', fileChanges)
+
+  info.changes = fileChanges
+  return info
+}
+
+module.exports = {
+  commitMeta,
+  isValidLine,
+  parseNumstat
+}
diff --git a/src/commit-numstat.js b/src/commit-numstat.js
index 8d58f78..404027e 100644
--- a/src/commit-numstat.js
+++ b/src/commit-numstat.js
@@ -1,79 +1,13 @@
 var la = require('lazy-ass')
 var check = require('check-more-types')
 var exec = require('./exec')
-
-// parses date, author, message
-function commitMeta (lines) {
-  la(lines.length > 3, 'expected more lines', lines)
-
-  var commit = lines[0].split(' ')[1].trim()
-  var author = lines[1].split(':')[1].trim()
-  // remove Date:
-  var date = lines[2].substr(5).trim()
-  var message = lines[4].trim()
-
-  return {
-    commit: commit,
-    author: author,
-    date: date,
-    message: message
-  }
-}
-
-/*
-parses git show --numstat output, which is something like this
-
-$ git show --numstat 46350c2
-commit 46350c2c9980551d338ce1ad0d8eff7bea9713ec
-Author: Gleb Bahmutov <gleb.bahmutov@gmail.com>
-Date:   Mon Jan 13 19:04:06 2014 -0500
-
-    better gruntfile
-
-1       1       .jshintrc
-54      25      Gruntfile.js
-9       0       complexity.json
-2       1       package.json
-*/
-function isValidLine (line) {
-  var rex = /^\s*\d+\s+\d+[\w\W]+$/
-  return line && rex.test(line)
-}
-la(isValidLine('1  1 time-method-call.js'))
-la(isValidLine(' 1  0 README.md'))
-
-function parseNumstat (stdout) {
-  la(check.unemptyString(stdout), 'missing numstat output', stdout)
-  var lines = stdout.split('\n')
-  la(lines.length > 3, 'expected more lines', stdout)
-
-  var info = commitMeta(lines)
-
-  var k = 6
-  var fileChanges = {}
-  for (; k < lines.length; k += 1) {
-    if (isValidLine(lines[k])) {
-      var parts = lines[k].split('\t')
-      var added = Number(parts[0].trim())
-      var deleted = Number(parts[1].trim())
-      var filename = parts[2].trim()
-      fileChanges[filename] = {
-        filename: filename,
-        added: added,
-        deleted: deleted
-      }
-    }
-  }
-
-  info.changes = fileChanges
-  return info
-}
+var { parseNumstat } = require('./commit-numstat-utils')
 
 function commitNumstat (hash) {
   la(check.unemptyString(hash), 'missing commit hash', hash)
 
   var cmd = 'git show --numstat ' + hash
-  return exec(cmd).then(parseNumstat)
+  return exec.exec(cmd).then(parseNumstat)
 }
 
 module.exports = commitNumstat
diff --git a/src/commit.js b/src/commit.js
index 97aaa64..3fd06b1 100644
--- a/src/commit.js
+++ b/src/commit.js
@@ -17,7 +17,7 @@ function commit (msg, longMessage) {
   }
 
   var cmd = 'git commit -am ' + quote(text)
-  return exec(cmd)
+  return exec.exec(cmd)
 }
 
 module.exports = commit
diff --git a/src/exec.js b/src/exec.js
index 51dca0d..b2c3181 100644
--- a/src/exec.js
+++ b/src/exec.js
@@ -28,4 +28,4 @@ function execPromise (cmd, verbose) {
   return deferred.promise
 }
 
-module.exports = execPromise
+module.exports = { exec: execPromise }
diff --git a/src/fetch-tags.js b/src/fetch-tags.js
index d586dcd..04735f7 100644
--- a/src/fetch-tags.js
+++ b/src/fetch-tags.js
@@ -7,7 +7,7 @@ function fetchTags (branch) {
   branch = branch || 'master'
   debug('fetching remote tags for branch', branch)
   var cmd = 'git pull origin ' + branch + ' --tags'
-  return exec(cmd)
+  return exec.exec(cmd)
 }
 
 module.exports = fetchTags
diff --git a/src/file-contents.js b/src/file-contents.js
index 20e0b4f..40e5e1f 100644
--- a/src/file-contents.js
+++ b/src/file-contents.js
@@ -13,7 +13,7 @@ function fileContents (filename, at) {
   })
   log('file contents command', cmd)
 
-  return exec(cmd).then(function (data) {
+  return exec.exec(cmd).then(function (data) {
     return data.trim()
   })
 }
diff --git a/src/file-status.js b/src/file-status.js
index a17a518..dc1b329 100644
--- a/src/file-status.js
+++ b/src/file-status.js
@@ -5,7 +5,8 @@ var R = require('ramda')
 var cmd = 'git status --porcelain'
 
 function fileStatus () {
-  return exec(cmd)
+  return exec
+    .exec(cmd)
     .then(R.tap(log))
     .then(stdoutToGroup)
     .then(R.tap(log))
diff --git a/src/get-one-line-log.js b/src/get-one-line-log.js
index d94137d..f93956d 100644
--- a/src/get-one-line-log.js
+++ b/src/get-one-line-log.js
@@ -27,7 +27,7 @@ function getLog (opts) {
   }
   debug('using log cmd "%s"', cmd)
 
-  return exec(cmd).then(logParser)
+  return exec.exec(cmd).then(logParser)
 }
 
 module.exports = getLog
diff --git a/src/git-folder.js b/src/git-folder.js
index ad21f70..98a1cd6 100644
--- a/src/git-folder.js
+++ b/src/git-folder.js
@@ -68,7 +68,8 @@ function stripSeparator (folder) {
 function getGitFolder () {
   const cmd = 'git rev-parse --show-toplevel'
   const verbose = /ggit/.test(process.env.DEBUG)
-  return exec(cmd, verbose)
+  return exec
+    .exec(cmd, verbose)
     .then(checkFolder, tryDotGit)
     .catch(searchUpForGitFolder)
     .then(folder => folder.trim())
diff --git a/src/has-changes.js b/src/has-changes.js
index 25c0263..0c8a1f2 100644
--- a/src/has-changes.js
+++ b/src/has-changes.js
@@ -8,7 +8,7 @@ function hasChanges () {
   var cmd = 'git diff --exit-code HEAD'
   // returns exit code 1 if there are changes
   // thus we reverse the true / false order
-  return exec(cmd).then(d3h.no, d3h.yes)
+  return exec.exec(cmd).then(d3h.no, d3h.yes)
 }
 
 module.exports = hasChanges
diff --git a/src/is-file-tracked.js b/src/is-file-tracked.js
index 6353b70..699c510 100644
--- a/src/is-file-tracked.js
+++ b/src/is-file-tracked.js
@@ -8,7 +8,7 @@ function isFileTracked (filename) {
   la(check.unemptyString(filename), 'missing filename')
   var fullPath = path.resolve(filename)
   var cmd = 'git ls-files --error-unmatch ' + fullPath
-  return exec(cmd).then(d3h.yes, d3h.no)
+  return exec.exec(cmd).then(d3h.yes, d3h.no)
 }
 
 module.exports = check.defend(
diff --git a/src/last-commit-id.js b/src/last-commit-id.js
index e59c3f1..645b664 100644
--- a/src/last-commit-id.js
+++ b/src/last-commit-id.js
@@ -35,7 +35,7 @@ function saveIntoFile (filename, build) {
 
 function getGitCommit () {
   var cmd = 'git log --format="%H" -n 1'
-  return exec(cmd)
+  return exec.exec(cmd)
 }
 
 function findCommit () {
diff --git a/src/push.js b/src/push.js
index 752a28c..6c65f38 100644
--- a/src/push.js
+++ b/src/push.js
@@ -2,7 +2,7 @@ var exec = require('./exec')
 
 function push (verbose) {
   var cmd = 'git push origin master --tags'
-  return exec(cmd, Boolean(verbose))
+  return exec.exec(cmd, Boolean(verbose))
 }
 
 module.exports = push
diff --git a/src/repo-root.js b/src/repo-root.js
index ec6190a..4da746d 100644
--- a/src/repo-root.js
+++ b/src/repo-root.js
@@ -1,7 +1,7 @@
 var exec = require('./exec')
 
 function getGitRootFolder (cb) {
-  return exec('git rev-parse --show-toplevel').then(
+  return exec.exec('git rev-parse --show-toplevel').then(
     function (path) {
       path = path.trim()
       if (cb) {
diff --git a/src/tags.js b/src/tags.js
index 5d30be3..e922949 100644
--- a/src/tags.js
+++ b/src/tags.js
@@ -31,7 +31,7 @@ function getTagCommit (tag) {
   debug('getting commit for tag "%s"', tag)
   debug('using command "%s"', cmd)
 
-  return exec(cmd).then(function (commit) {
+  return exec.exec(cmd).then(function (commit) {
     return {
       commit: commit.trim(),
       tag: tag
@@ -59,7 +59,8 @@ function getBranchTags (vTagsOnly) {
   // only tags accessible from the current branch are returned
   var cmd = 'git tag --sort version:refname --merged'
   var parseSomeTags = parseTags.bind(null, vTagsOnly)
-  return exec(cmd)
+  return exec
+    .exec(cmd)
     .then(parseSomeTags)
     .then(getCommitIds)
 }
@@ -67,7 +68,8 @@ function getBranchTags (vTagsOnly) {
 function getTagsSortByVersion () {
   const cmd = 'git tag'
   // return single string so other pieces work as expected
-  return exec(cmd)
+  return exec
+    .exec(cmd)
     .then(sortTagsByVersion)
     .then(tags => tags.join('\n'))
 }
@@ -77,7 +79,8 @@ function getTags (vTagsOnly) {
   // oldest tags first, latest tags last
   var cmd = 'git tag --sort version:refname'
   var parseSomeTags = parseTags.bind(null, vTagsOnly)
-  return exec(cmd)
+  return exec
+    .exec(cmd)
     .catch(getTagsSortByVersion)
     .then(parseSomeTags)
     .then(getCommitIds)
diff --git a/src/untracked-files.js b/src/untracked-files.js
index 9ce51cf..4ad3366 100644
--- a/src/untracked-files.js
+++ b/src/untracked-files.js
@@ -11,7 +11,7 @@ function cleanList (list) {
 
 function untrackedFiles () {
   var cmd = 'git ls-files --others --exclude-standard'
-  return exec(cmd).then(cleanList)
+  return exec.exec(cmd).then(cleanList)
 }
 
 module.exports = untrackedFiles
diff --git a/src/utils.js b/src/utils.js
index 72a129d..94dacda 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -84,7 +84,7 @@ function getCircleCiCommit () {
 
 function getGitCommit () {
   var cmd = 'git log --format="%H" -n 1'
-  return exec(cmd)
+  return exec.exec(cmd)
 }
 
 function findCommit () {
@@ -104,9 +104,13 @@ function buildInfo (options) {
   options = options || {}
 
   function getMessage (id) {
-    return options.message
-      ? numstat(id).then(R.prop('message'))
-      : Promise.resolve()
+    if (!options.message) {
+      debug('no need to get commit message for %s', id)
+      return Promise.resolve()
+    }
+
+    debug('getMessage for commit %s', id)
+    return numstat(id).then(R.prop('message'))
   }
 
   var commitId