[None][test] CBTS coverage HTML: show per-line test contexts

Enable coverage.py's show_contexts in the rendered HTML report so each
covered line carries a clickable list of the pytest nodeids that
exercised it. The data was already being captured -- cbts_plugin and
sitecustomize call cov.switch_context(nodeid) per test on both the
pytest main and MPI worker sides -- but the post-job HTML rendering in
L0_MergeRequest's "Test Coverage" stage was not asking for it.

Three .coveragerc-touching changes:

* jenkins/L0_MergeRequest.groovy "Test Coverage" stage: rewrite the
  combine-time rcfile as a heredoc, add [html] show_contexts = True,
  and pass --show-contexts on the coverage html invocation. No-op for
  legacy non-CBTS stages whose .coverage carries no context info.

* jenkins/L0_Test.groovy isCbtsStage(...) branch and
  jenkins/scripts/cbts/coverage_utils/coveragerc.template: same
  [html] block so a manually-rendered HTML report uses the per-stage
  rcfile.

No behavior change to test execution. Affects only the rendering step
that runs after combine on the Jenkins controller.

Signed-off-by: Ivy Zhang <25222398+crazydemo@users.noreply.github.com>

Author: crazydemo

jenkins/L0_MergeRequest.groovy

@@ -1173,16 +1173,34 @@ def collectTestResults(pipeline, testFilter)
                 sh "cp llm/examples/openai_triton/manual_plugin/fmha_triton.py llm/examples/openai_triton/plugin_autogen/"
                 def coverageConfigFile = "cov/.coveragerc"
                 sh """
-                    echo '[paths]' > ${coverageConfigFile}
-                    echo 'source1=\n    ${CUR_PATH}/llm/examples/\n    */TensorRT-LLM/src/examples/' >> ${coverageConfigFile}
-                    echo 'source2=\n    ${CUR_PATH}/llm/tensorrt_llm/\n    */tensorrt_llm/' >> ${coverageConfigFile}
+                    cat > ${coverageConfigFile} <<'EOF'
+[paths]
+source1 =
+    ${CUR_PATH}/llm/examples/
+    */TensorRT-LLM/src/examples/
+source2 =
+    ${CUR_PATH}/llm/tensorrt_llm/
+    */tensorrt_llm/
+
+[html]
+# Per-line "which tests covered this" annotations in the rendered HTML
+# report. Pairs with cov.switch_context() calls in cbts_plugin /
+# sitecustomize that tag each line with the pytest nodeid that
+# triggered it. No-op for non-CBTS stages whose .coverage files
+# carry no context info.
+show_contexts = True
+EOF
                     cat ${coverageConfigFile}
                 """
 
                 sh "cd cov && coverage combine"
                 sh "cd cov && find . -type f"
                 sh "cd cov && coverage report -i"   // -i: ignore errors. Ignore the error that the source code file cannot be found.
-                sh "cd cov && coverage html -d test_coverage_html -i"
+                // --show-contexts pairs with show_contexts=True in .coveragerc
+                // [html] section: each line in the rendered HTML gets a
+                // clickable list of test nodeids that covered it. For non-CBTS
+                // stages whose .coverage carries no context info this is a no-op.
+                sh "cd cov && coverage html -d test_coverage_html -i --show-contexts"
                 trtllm_utils.uploadArtifacts("cov/test_coverage_html/*", "${UPLOAD_PATH}/test-results/coverage-report/")
                 echo "Test coverage report: https://urm.nvidia.com/artifactory/${UPLOAD_PATH}/test-results/coverage-report/index.html"
             } // Test coverage

jenkins/L0_Test.groovy

@@ -1144,6 +1144,13 @@ source =
 
 [report]
 ignore_errors = True
+
+[html]
+# Per-line "which tests covered this" annotations in the rendered HTML
+# report (clickable contexts list). Pairs with cov.switch_context()
+# calls in cbts_plugin / sitecustomize that tag each line with the
+# pytest nodeid that triggered it.
+show_contexts = True
 EOF
                         cat ./.coveragerc
                     """

jenkins/scripts/cbts/coverage_utils/coveragerc.template

@@ -48,3 +48,10 @@ source =
 
 [report]
 ignore_errors = True
+
+[html]
+# Per-line "which tests covered this" annotations in the rendered HTML
+# report (clickable contexts list). Pairs with cov.switch_context()
+# calls in cbts_plugin / sitecustomize that tag each line with the
+# pytest nodeid that triggered it.
+show_contexts = True