add codecoverage

.

Author: vladimir-popov

.github/workflows/ci.yml

@@ -11,9 +11,26 @@ on:
 
 jobs:
   test:
+    name: Build, Test and Check coverage
     runs-on: ubuntu-latest
-    name: Build and Test
     steps:
-      - uses: actions/checkout@v3
-      - uses: mlugg/setup-zig@v1
-      - run: zig build test --summary all
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 2
+
+      - name: Install kcov
+        run: sudo apt-get install -y kcov
+
+      - name: Install zig
+        uses: mlugg/setup-zig@v1
+
+      - name: Zig build test
+        run: zig build test -Dtest-coverage --summary all
+
+      - name: Upload results to Codecov
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          directory: ./coverage/
+          fail_ci_if_error: true

.gitignore

@@ -1,2 +1,4 @@
 .zig-cache/
 zig-out/
+kcov-output/
+coverage/

build.zig

@@ -36,13 +36,28 @@ pub fn build(b: *std.Build) void {
         "Skip tests that do not match any filter",
     ) orelse &[0][]const u8{};
 
+    // -Dtest-coverage
+    const coverage = b.option(
+        bool,
+        "test-coverage",
+        "Generate test coverage",
+    ) orelse false;
+
     const parcom_tests = b.addTest(.{
-        .root_source_file = b.path("src/parcom.zig"),
-        .target = target,
-        .optimize = optimize,
+        .root_module = parcom,
         .filters = test_filters,
     });
 
+    if (coverage) {
+        parcom_tests.setExecCmd(&[_]?[]const u8{
+            "kcov",
+            "--include-path=src/parcom.zig",
+            "--dump-summary",
+            "./coverage",
+            null, // to get zig to use the --test-cmd-bin flag
+        });
+    }
+
     const run_parcom_tests = b.addRunArtifact(parcom_tests);
 
     const test_step = b.step("test", "Run unit tests");