Merge f4bc8bf into ff2bec3

src/python/pants/backend/python/rules/coverage.py

@@ -276,6 +276,11 @@ async def generate_coverage_reports(
             )
             continue
         report_types.append(report_type)
+        output_file = (
+            f"coverage.{report_type.value}"
+            if report_type in {CoverageReportType.XML, CoverageReportType.JSON}
+            else None
+        )
         pex_processes.append(
             PexProcess(
                 coverage_setup.pex,
@@ -284,7 +289,7 @@ async def generate_coverage_reports(
                 argv=(report_type.report_name, "--ignore-errors"),
                 input_digest=input_digest,
                 output_directories=("htmlcov",) if report_type == CoverageReportType.HTML else None,
-                output_files=("coverage.xml",) if report_type == CoverageReportType.XML else None,
+                output_files=(output_file,) if output_file else None,
                 description=f"Generate Pytest {report_type.report_name} coverage report.",
                 level=LogLevel.DEBUG,
             )
@@ -312,6 +317,8 @@ def _get_coverage_reports(
             report_file = output_dir / "htmlcov" / "index.html"
         elif report_type == CoverageReportType.XML:
             report_file = output_dir / "coverage.xml"
+        elif report_type == CoverageReportType.JSON:
+            report_file = output_dir / "coverage.json"
         else:
             raise ValueError(f"Invalid coverage report type: {report_type}")
         coverage_reports.append(

src/python/pants/backend/python/rules/coverage_integration_test.py

@@ -218,11 +218,13 @@ def test_coverage_raw(self) -> None:
             result = self._run_tests(tmpdir_relative, "--coverage-py-report=raw")
             self._assert_raw_coverage(result, build_root)
 
-    def test_coverage_html_and_xml(self) -> None:
+    def test_coverage_html_xml_json(self) -> None:
         build_root = get_buildroot()
         with temporary_dir(root_dir=build_root) as tmpdir:
             tmpdir_relative = self._prepare_sources(tmpdir, build_root)
-            result = self._run_tests(tmpdir_relative, "--coverage-py-report=['xml', 'html']")
+            result = self._run_tests(
+                tmpdir_relative, "--coverage-py-report=['xml', 'html', 'json']"
+            )
             coverage_path = Path(build_root, "dist", "coverage", "python")
             assert coverage_path.exists() is True
 
@@ -234,3 +236,7 @@ def test_coverage_html_and_xml(self) -> None:
             html_cov_dir = coverage_path / "htmlcov"
             assert html_cov_dir.exists() is True
             assert (html_cov_dir / "index.html").exists() is True
+
+            assert "Wrote json coverage report to `dist/coverage/python`" in result.stderr_data
+            json_coverage = coverage_path / "coverage.json"
+            assert json_coverage.exists() is True

src/python/pants/core/goals/test.py

@@ -39,6 +39,7 @@ class CoverageReportType(Enum):
     XML = ("xml", None)
     HTML = ("html", None)
     RAW = ("raw", None)
+    JSON = ("json", None)
 
     _report_name: str