Add --scan-dryrun-results for Maven subset to honor pom.xml test filtering

launchable/test_runners/maven.py

@@ -1,6 +1,7 @@
 import glob
 import os
 import re
+import xml.etree.ElementTree as ET
 from typing import Dict, List, Optional, Tuple
 
 import click
@@ -46,6 +47,31 @@ def is_file(f: str) -> bool:
     return False
 
 
+def parse_surefire_reports() -> List[Dict[str, str]]:
+    """Collect the test classes Surefire discovered from its TEST-*.xml reports.
+
+    Intended to be run against reports produced by a JUnit 5 dry run
+    (`mvn test -Djunit.platform.execution.dryRun.enabled=true`): Surefire applies
+    all of its own filtering (excludedGroups, includedGroups, excludes, profiles,
+    ...) before the dry run, so only the tests Maven would actually execute get a
+    report. Each report's root `name` attribute is the fully-qualified class name.
+    """
+    test_paths = []
+    report_pattern = os.path.join('**', 'target', 'surefire-reports', 'TEST-*.xml')
+    report_files = glob.glob(report_pattern, recursive=True)
+
+    for report_file in report_files:
+        try:
+            classname = ET.parse(report_file).getroot().get('name')
+            if classname:
+                test_paths.append({"type": "class", "name": classname})
+        except ET.ParseError as e:
+            click.echo(click.style(
+                "Warning: Could not parse {}: {}".format(report_file, e), fg="yellow"), err=True)
+
+    return test_paths
+
+
 @click.option(
     '--test-compile-created-file',
     'test_compile_created_file',
@@ -61,6 +87,13 @@ def is_file(f: str) -> bool:
     is_flag=True,
     help="Scan testCompile/default-testCompile/createdFiles.lst for *.lst files generated by `mvn compile` and use them as test inputs.",  # noqa: E501
 )
+@click.option(
+    '--scan-dryrun-results',
+    'is_scan_dryrun_results',
+    required=False,
+    is_flag=True,
+    help="Scan surefire reports generated by `mvn test -Djunit.platform.execution.dryRun.enabled=true`. Only the tests Maven would actually run (after applying pom.xml excludedGroups/excludes/etc.) are sent to the subset. Run the dry run before this command. JUnit 5 only.",  # noqa: E501
+)
 @click.option(
     '--exclude',
     'exclude_rules',
@@ -70,7 +103,19 @@ def is_file(f: str) -> bool:
 )
 @click.argument('source_roots', required=False, nargs=-1)
 @launchable.subset
-def subset(client, source_roots, test_compile_created_file, is_scan_test_compile_lst, exclude_rules: Tuple[str, ...]):
+def subset(client, source_roots, test_compile_created_file, is_scan_test_compile_lst, is_scan_dryrun_results,
+           exclude_rules: Tuple[str, ...]):
+
+    if is_scan_dryrun_results:
+        tests = parse_surefire_reports()
+        if not tests:
+            raise click.UsageError(
+                "No surefire reports found under **/target/surefire-reports/. "
+                "Run `mvn test -Djunit.platform.execution.dryRun.enabled=true` before this command.")
+        for test in tests:
+            client.test_paths.append([test])
+        client.run()
+        return
 
     # Compile exclude rules
     compiled_exclude_rules = []

tests/data/maven/dryrun-test/target/surefire-reports/TEST-com.example.launchable.CalculatorTest.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<testsuite name="com.example.launchable.CalculatorTest" time="0" tests="1" errors="0" skipped="1" failures="0">
+  <testcase name="add" classname="com.example.launchable.CalculatorTest" time="0">
+    <skipped/>
+  </testcase>
+</testsuite>

tests/data/maven/dryrun-test/target/surefire-reports/TEST-com.example.launchable.UserTest.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<testsuite name="com.example.launchable.UserTest" time="0" tests="1" errors="0" skipped="1" failures="0">
+  <testcase name="create" classname="com.example.launchable.UserTest" time="0">
+    <skipped/>
+  </testcase>
+</testsuite>

tests/data/maven/subset_scan_dryrun_results_result.json

@@ -0,0 +1,12 @@
+{
+  "testPaths": [
+    [{"type": "class", "name": "com.example.launchable.CalculatorTest"}],
+    [{"type": "class", "name": "com.example.launchable.UserTest"}]
+  ],
+  "testRunner": "maven",
+  "goal": {"type": "subset-by-percentage", "percentage": 0.1},
+  "ignoreNewTests": false,
+  "session": {"id": "16"},
+  "getTestsFromGuess": false,
+  "getTestsFromPreviousSessions": false
+}

tests/test_runners/test_maven.py

@@ -227,6 +227,36 @@ def test_subset_with_exclude(self):
         self.assert_success(result)
         self.assert_subset_payload('subset_with_exclude_rules_result.json')
 
+    @responses.activate
+    @mock.patch.dict(os.environ, {"LAUNCHABLE_TOKEN": CliTestCase.launchable_token})
+    def test_scan_dryrun_results(self):
+        # Reports live under <dryrun-test>/target/surefire-reports/. The flag globs
+        # **/target/surefire-reports/TEST-*.xml relative to the cwd, so run from there.
+        test_data_dir = str(self.test_files_dir.joinpath('dryrun-test').resolve())
+        original_dir = os.getcwd()
+        try:
+            os.chdir(test_data_dir)
+            result = self.cli('subset', '--target', '10%', '--session',
+                              self.session, 'maven', '--scan-dryrun-results')
+            self.assert_success(result)
+            self.assert_subset_payload('subset_scan_dryrun_results_result.json')
+        finally:
+            os.chdir(original_dir)
+
+    @responses.activate
+    @mock.patch.dict(os.environ, {"LAUNCHABLE_TOKEN": CliTestCase.launchable_token})
+    def test_scan_dryrun_results_no_reports(self):
+        original_dir = os.getcwd()
+        with tempfile.TemporaryDirectory() as temp_dir:
+            try:
+                os.chdir(temp_dir)
+                result = self.cli('subset', '--target', '10%', '--session',
+                                  self.session, 'maven', '--scan-dryrun-results')
+                self.assertNotEqual(result.exit_code, 0)
+                self.assertIn("No surefire reports found", result.output)
+            finally:
+                os.chdir(original_dir)
+
     def test_glob(self):
         for x in [
             'foo/BarTest.java',