Collect coverage from cc_binary data deps of py_test

Before this commit, if a py_test executed a cc_binary from its data
deps, coverage for this cc_binary would not be collected. This is fixed
by adding the implicit `$collect_cc_coverage` attribute to
BazelPyTestRule, similar to how this is already done for
BazelShTestRule.

Fixes bazelbuild#15098.

Closes bazelbuild#15097.

PiperOrigin-RevId: 442800790

src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPyTestRule.java

@@ -58,6 +58,13 @@ public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment env)
                 .cfg(HostTransition.createFactory())
                 .value(env.getToolsLabel("//tools/launcher:launcher")))
         .add(attr(":lcov_merger", LABEL).value(BaseRuleClasses.getCoverageOutputGeneratorLabel()))
+        // Add the script as an attribute in order for py_test to output code coverage results for
+        // code covered by CC binaries invocations.
+        .add(
+            attr("$collect_cc_coverage", LABEL)
+                .cfg(HostTransition.createFactory())
+                .singleArtifact()
+                .value(env.getToolsLabel("//tools/test:collect_cc_coverage")))
         .build();
   }
 

src/test/shell/bazel/BUILD

@@ -555,6 +555,15 @@ sh_test(
     for java_version in JAVA_VERSIONS_COVERAGE
 ]
 
+sh_test(
+    name = "bazel_coverage_py_test",
+    srcs = ["bazel_coverage_py_test.sh"],
+    data = [":test-deps"],
+    tags = [
+        "no_windows",
+    ],
+)
+
 sh_test(
     name = "bazel_coverage_sh_test",
     srcs = ["bazel_coverage_sh_test.sh"],