From 9163fb08877d4d21b9aef367e5b81d24c0d75ed4 Mon Sep 17 00:00:00 2001
From: AriPerkkio <ari.perkkio@gmail.com>
Date: Tue, 28 Feb 2023 20:00:38 +0200
Subject: [PATCH] test: empty coverage

---
 test/fixtures/scripts/uncovered.js |  7 +++++++
 test/v8-to-istanbul.js             | 26 ++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 test/fixtures/scripts/uncovered.js

diff --git a/test/fixtures/scripts/uncovered.js b/test/fixtures/scripts/uncovered.js
new file mode 100644
index 00000000..9f94e563
--- /dev/null
+++ b/test/fixtures/scripts/uncovered.js
@@ -0,0 +1,7 @@
+function uncoveredFunction() {
+  return "Hello world";
+}
+
+if ("Branches here" === false) {
+  uncoveredFunction();
+}
diff --git a/test/v8-to-istanbul.js b/test/v8-to-istanbul.js
index 7a2c6938..b776ce00 100644
--- a/test/v8-to-istanbul.js
+++ b/test/v8-to-istanbul.js
@@ -207,6 +207,32 @@ ${'//'}${'#'} sourceMappingURL=data:application/json;base64,${base64Sourcemap}
     assert(v8ToIstanbul.sourceMap !== undefined)
   })
 
+  it('empty coverage marks all lines uncovered', async () => {
+    const filename = require.resolve('./fixtures/scripts/uncovered.js')
+    const v8ToIstanbul = new V8ToIstanbul(filename)
+
+    await v8ToIstanbul.load()
+    v8ToIstanbul.applyCoverage([{
+      functionName: '(empty-report)',
+      ranges: [{
+        startOffset: 0,
+        endOffset: lstatSync(filename).size,
+        count: 0
+      }],
+      isBlockCoverage: true
+    }])
+
+    v8ToIstanbul.toIstanbul()[filename].s.should.eql({
+      0: 0,
+      1: 0,
+      2: 0,
+      3: 0,
+      4: 0,
+      5: 0,
+      6: 0
+    })
+  })
+
   // execute JavaScript files in fixtures directory; these
   // files contain the raw v8 output along with a set of
   // assertions. the original scripts can be found in the