add codecov

.travis.yml

@@ -1,10 +1,21 @@
 language: go
-
+sudo: false
 go:
   - 1.3.x
   - 1.4.x
   - 1.5.x
   - 1.6.x
   - 1.7.x
   - 1.8.x
+  - 1.8.x
   - master
+  - tip
+
+before_install:
+  - go get -t -v ./...
+
+script:
+  - ./go.test.sh
+
+after_success:
+  - bash <(curl -s https://codecov.io/bash)

test.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+set -e
+echo "" > coverage.txt
+
+for d in $(go list ./...); do
+    go test -coverprofile=profile.out -covermode=atomic "$d"
+    if [ -f profile.out ]; then
+        cat profile.out >> coverage.txt
+        rm profile.out
+    fi
+done