[jvm] Hook up the ability to run JUnit tests written in Scala (pantsb…

…uild#13868)

The `scala_junit_tests` target was added in pantsbuild#13130, and became compilable from the JUnit `@rules` in pantsbuild#13519. The final piece to enable actual usage is to allow the JUnit `@rules` to match non-Java sources.

This change adds the `JunitTestSourceField` marker, which is extended by `JavaJunitTestSourceField` and `ScalaJunitTestSourceField`, and tests that JUnit tests can be written in Scala.

[ci skip-rust]

pants.toml

@@ -176,7 +176,7 @@ java_parser = "src/python/pants/backend/java/dependency_inference/java_parser.lo
 scala_parser = "src/python/pants/backend/scala/dependency_inference/scala_parser.lockfile"
 
 [junit]
-lockfile = "src/python/pants/backend/java/test/junit.default.lockfile.txt"
+lockfile = "src/python/pants/jvm/junit.default.lockfile.txt"
 
 [google-java-format]
 lockfile = "src/python/pants/backend/java/lint/google_java_format/google_java_format.default.lockfile.txt"

src/python/pants/backend/experimental/java/register.py

@@ -14,13 +14,13 @@
     JunitTestTarget,
 )
 from pants.backend.java.target_types import rules as target_types_rules
-from pants.backend.java.test import junit
 from pants.jvm import classpath, jdk_rules
 from pants.jvm import util_rules as jvm_util_rules
 from pants.jvm.dependency_inference import symbol_mapper
 from pants.jvm.goals import coursier
 from pants.jvm.resolve import coursier_fetch, coursier_setup, jvm_tool
 from pants.jvm.target_types import JvmArtifact
+from pants.jvm.test import junit
 
 
 def target_types():

src/python/pants/backend/experimental/scala/register.py

@@ -1,12 +1,7 @@
 # Copyright 2021 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 from pants.backend.java.package import deploy_jar  # TODO: Should move to the JVM package.
-from pants.backend.java.target_types import (  # TODO: All of these should move to the JVM package.
-    DeployJar,
-    JunitTestsGeneratorTarget,
-    JunitTestTarget,
-)
-from pants.backend.java.test import junit  # TODO: Should move to the JVM package.
+from pants.backend.java.target_types import DeployJar  # TODO: Should move to the JVM package.
 from pants.backend.scala.compile import scalac
 from pants.backend.scala.dependency_inference import rules as dep_inf_rules
 from pants.backend.scala.goals import check, repl, tailor
@@ -22,13 +17,12 @@
 from pants.jvm.goals import coursier
 from pants.jvm.resolve import coursier_fetch, coursier_setup, jvm_tool
 from pants.jvm.target_types import JvmArtifact
+from pants.jvm.test import junit
 
 
 def target_types():
     return [
         DeployJar,
-        JunitTestTarget,
-        JunitTestsGeneratorTarget,
         JvmArtifact,
         ScalaJunitTestTarget,
         ScalaJunitTestsGeneratorTarget,

src/python/pants/backend/java/dependency_inference/rules_test.py

@@ -18,7 +18,6 @@
     JunitTestsGeneratorTarget,
 )
 from pants.backend.java.target_types import rules as java_target_rules
-from pants.backend.java.test.junit import rules as junit_rules
 from pants.core.util_rules import config_files, source_files
 from pants.core.util_rules.external_tool import rules as external_tool_rules
 from pants.engine.addresses import Address, Addresses, UnparsedAddressInputs
@@ -33,6 +32,7 @@
 from pants.jvm.resolve.coursier_fetch import rules as coursier_fetch_rules
 from pants.jvm.resolve.coursier_setup import rules as coursier_setup_rules
 from pants.jvm.target_types import JvmArtifact
+from pants.jvm.test.junit import rules as junit_rules
 from pants.jvm.testutil import maybe_skip_jdk_test
 from pants.jvm.util_rules import rules as util_rules
 from pants.testutil.rule_runner import PYTHON_BOOTSTRAP_ENV, QueryRule, RuleRunner

src/python/pants/backend/java/subsystems/junit.py

@@ -15,8 +15,8 @@ class JUnit(JvmToolBase):
         "org.junit.jupiter:junit-jupiter-engine:{version}",
         "org.junit.vintage:junit-vintage-engine:{version}",
     )
-    default_lockfile_resource = ("pants.backend.java.test", "junit.default.lockfile.txt")
-    default_lockfile_url = git_url("src/python/pants/backend/java/test/junit.default.lockfile.txt")
+    default_lockfile_resource = ("pants.jvm.test", "junit.default.lockfile.txt")
+    default_lockfile_url = git_url("src/python/pants/jvm/test/junit.default.lockfile.txt")
 
     @classmethod
     def register_options(cls, register):

src/python/pants/backend/java/target_types.py

@@ -23,6 +23,7 @@
 )
 from pants.engine.unions import UnionMembership, UnionRule
 from pants.jvm.target_types import (
+    JunitTestSourceField,
     JvmCompatibleResolveNamesField,
     JvmProvidesTypesField,
     JvmResolveNameField,
@@ -56,15 +57,15 @@ class JavaGeneratorFieldSet(FieldSet):
 # -----------------------------------------------------------------------------------------------
 
 
-class JavaTestSourceField(JavaSourceField):
-    pass
+class JavaJunitTestSourceField(JavaSourceField, JunitTestSourceField):
+    """A JUnit test file written in Java."""
 
 
 class JunitTestTarget(Target):
     alias = "junit_test"
     core_fields = (
         *COMMON_TARGET_FIELDS,
-        JavaTestSourceField,
+        JavaJunitTestSourceField,
         Dependencies,
         JvmCompatibleResolveNamesField,
         JvmProvidesTypesField,

src/python/pants/backend/scala/target_types.py

@@ -21,7 +21,11 @@
     generate_file_level_targets,
 )
 from pants.engine.unions import UnionMembership, UnionRule
-from pants.jvm.target_types import JvmCompatibleResolveNamesField, JvmProvidesTypesField
+from pants.jvm.target_types import (
+    JunitTestSourceField,
+    JvmCompatibleResolveNamesField,
+    JvmProvidesTypesField,
+)
 
 
 class ScalaSourceField(SingleSourceField):
@@ -47,11 +51,11 @@ class ScalaGeneratorFieldSet(FieldSet):
 
 
 # -----------------------------------------------------------------------------------------------
-# `junit_test` target
+# `scala_junit_test` target
 # -----------------------------------------------------------------------------------------------
 
 
-class ScalaTestSourceField(ScalaSourceField):
+class ScalaTestSourceField(ScalaSourceField, JunitTestSourceField):
     pass
 
 

src/python/pants/jvm/target_types.py

@@ -3,17 +3,22 @@
 
 from __future__ import annotations
 
+from abc import ABCMeta
+
 from pants.engine.target import (
     COMMON_TARGET_FIELDS,
     FieldSet,
     SingleSourceField,
-    SpecialCasedDependencies,
     StringField,
     StringSequenceField,
     Target,
 )
 from pants.util.docutil import git_url
 
+# -----------------------------------------------------------------------------------------------
+# `jvm_artifact` targets
+# -----------------------------------------------------------------------------------------------
+
 _DEFAULT_PACKAGE_MAPPING_URL = git_url(
     "src/python/pants/jvm/dependency_inference/jvm_artifact_mappings.py"
 )
@@ -123,6 +128,20 @@ class JvmArtifact(Target):
     )
 
 
+# -----------------------------------------------------------------------------------------------
+# JUnit test support field(s)
+# -----------------------------------------------------------------------------------------------
+
+
+class JunitTestSourceField(SingleSourceField, metaclass=ABCMeta):
+    """A marker that indicates that a source field represents a JUnit test."""
+
+
+# -----------------------------------------------------------------------------------------------
+# Generic resolve support fields
+# -----------------------------------------------------------------------------------------------
+
+
 class JvmCompatibleResolveNamesField(StringSequenceField):
     alias = "compatible_resolves"
     required = False
@@ -141,12 +160,3 @@ class JvmResolveNameField(StringField):
         "one of the resolves in `--jvm-resolves`. If not supplied, the default resolve will be "
         "used, otherwise, one resolve that is compatible with all dependency targets will be used."
     )
-
-
-class JvmRequirementsField(SpecialCasedDependencies):
-    alias = "requirements"
-    required = True
-    help = (
-        "A sequence of addresses to targets compatible with `jvm_artifact` that specify the coordinates for "
-        "third-party JVM dependencies."
-    )

src/python/pants/backend/java/test/junit.py → src/python/pants/jvm/test/junit.py

@@ -5,7 +5,6 @@
 from dataclasses import dataclass
 
 from pants.backend.java.subsystems.junit import JUnit
-from pants.backend.java.target_types import JavaTestSourceField
 from pants.core.goals.test import TestDebugRequest, TestFieldSet, TestResult, TestSubsystem
 from pants.engine.addresses import Addresses
 from pants.engine.fs import Digest, DigestSubset, MergeDigests, PathGlobs, RemovePrefix, Snapshot
@@ -16,16 +15,17 @@
 from pants.jvm.jdk_rules import JdkSetup
 from pants.jvm.resolve.coursier_fetch import MaterializedClasspath, MaterializedClasspathRequest
 from pants.jvm.resolve.jvm_tool import JvmToolLockfileRequest, JvmToolLockfileSentinel
+from pants.jvm.target_types import JunitTestSourceField
 from pants.util.logging import LogLevel
 
 logger = logging.getLogger(__name__)
 
 
 @dataclass(frozen=True)
-class JavaTestFieldSet(TestFieldSet):
-    required_fields = (JavaTestSourceField,)
+class JunitTestFieldSet(TestFieldSet):
+    required_fields = (JunitTestSourceField,)
 
-    sources: JavaTestSourceField
+    sources: JunitTestSourceField
 
 
 class JunitToolLockfileSentinel(JvmToolLockfileSentinel):
@@ -38,7 +38,7 @@ async def run_junit_test(
     jdk_setup: JdkSetup,
     junit: JUnit,
     test_subsystem: TestSubsystem,
-    field_set: JavaTestFieldSet,
+    field_set: JunitTestFieldSet,
 ) -> TestResult:
     classpath, junit_classpath = await MultiGet(
         Get(Classpath, Addresses([field_set.address])),
@@ -108,7 +108,7 @@ async def run_junit_test(
 
 # Required by standard test rules. Do nothing for now.
 @rule(level=LogLevel.DEBUG)
-async def setup_junit_debug_request(_field_set: JavaTestFieldSet) -> TestDebugRequest:
+async def setup_junit_debug_request(_field_set: JunitTestFieldSet) -> TestDebugRequest:
     raise NotImplementedError("TestDebugResult is not implemented for JUnit (yet?).")
 
 
@@ -122,6 +122,6 @@ async def generate_junit_lockfile_request(
 def rules():
     return [
         *collect_rules(),
-        UnionRule(TestFieldSet, JavaTestFieldSet),
+        UnionRule(TestFieldSet, JunitTestFieldSet),
         UnionRule(JvmToolLockfileSentinel, JunitToolLockfileSentinel),
     ]

src/python/pants/backend/java/test/junit_test.py → src/python/pants/jvm/test/junit_test.py

@@ -11,8 +11,9 @@
 from pants.backend.java.compile.javac import rules as javac_rules
 from pants.backend.java.target_types import JavaSourcesGeneratorTarget, JunitTestsGeneratorTarget
 from pants.backend.java.target_types import rules as target_types_rules
-from pants.backend.java.test.junit import JavaTestFieldSet
-from pants.backend.java.test.junit import rules as junit_rules
+from pants.backend.scala.compile.scalac import rules as scalac_rules
+from pants.backend.scala.target_types import ScalaJunitTestsGeneratorTarget
+from pants.backend.scala.target_types import rules as scala_target_types_rules
 from pants.build_graph.address import Address
 from pants.core.goals.test import TestResult
 from pants.core.util_rules import config_files, source_files
@@ -31,6 +32,8 @@
 from pants.jvm.resolve.coursier_fetch import rules as coursier_fetch_rules
 from pants.jvm.resolve.coursier_setup import rules as coursier_setup_rules
 from pants.jvm.target_types import JvmArtifact
+from pants.jvm.test.junit import JunitTestFieldSet
+from pants.jvm.test.junit import rules as junit_rules
 from pants.jvm.testutil import maybe_skip_jdk_test
 from pants.jvm.util_rules import rules as util_rules
 from pants.testutil.rule_runner import PYTHON_BOOTSTRAP_ENV, QueryRule, RuleRunner
@@ -46,24 +49,27 @@ def rule_runner() -> RuleRunner:
     rule_runner = RuleRunner(
         preserve_tmpdirs=True,
         rules=[
-            *config_files.rules(),
             *classpath.rules(),
+            *config_files.rules(),
             *coursier_fetch_rules(),
             *coursier_setup_rules(),
             *external_tool_rules(),
-            *source_files.rules(),
+            *java_util_rules(),
             *javac_rules(),
             *junit_rules(),
-            *util_rules(),
-            *java_util_rules(),
+            *scala_target_types_rules(),
+            *scalac_rules(),
+            *source_files.rules(),
             *target_types_rules(),
+            *util_rules(),
             QueryRule(CoarsenedTargets, (Addresses,)),
-            QueryRule(TestResult, (JavaTestFieldSet,)),
+            QueryRule(TestResult, (JunitTestFieldSet,)),
         ],
         target_types=[
             JvmArtifact,
             JavaSourcesGeneratorTarget,
             JunitTestsGeneratorTarget,
+            ScalaJunitTestsGeneratorTarget,
         ],
     )
     rule_runner.set_options(
@@ -240,7 +246,6 @@ def test_vintage_success_with_dep(rule_runner: RuleRunner) -> None:
 
                 java_sources(
                     name='example-lib',
-
                 )
 
                 junit_tests(
@@ -289,6 +294,53 @@ def test_vintage_success_with_dep(rule_runner: RuleRunner) -> None:
     assert re.search(r"1 tests found", test_result.stdout) is not None
 
 
+@maybe_skip_jdk_test
+def test_vintage_scala_simple_success(rule_runner: RuleRunner) -> None:
+    rule_runner.write_files(
+        {
+            "coursier_resolve.lockfile": JUNIT4_RESOLVED_LOCKFILE.to_json().decode("utf-8"),
+            "BUILD": dedent(
+                """\
+                jvm_artifact(
+                  name = 'junit_junit',
+                  group = 'junit',
+                  artifact = 'junit',
+                  version = '4.13.2',
+                )
+
+                scala_junit_tests(
+                    name='example-test',
+                    dependencies= [
+                        ':junit_junit',
+                    ],
+                )
+                """
+            ),
+            "SimpleTest.scala": dedent(
+                """
+                package org.pantsbuild.example
+
+                import junit.framework.TestCase
+                import junit.framework.Assert._
+
+                class SimpleTest extends TestCase {
+                   def testHello(): Unit = {
+                      assertTrue("Hello!" == "Hello!")
+                   }
+                }
+                """
+            ),
+        }
+    )
+
+    test_result = run_junit_test(rule_runner, "example-test", "SimpleTest.scala")
+
+    assert test_result.exit_code == 0
+    assert re.search(r"Finished:\s+testHello", test_result.stdout) is not None
+    assert re.search(r"1 tests successful", test_result.stdout) is not None
+    assert re.search(r"1 tests found", test_result.stdout) is not None
+
+
 # This is hard-coded to make the test somewhat more hermetic.
 # To regenerate (e.g. to update the resolved version), run the
 # following in a test:
@@ -560,4 +612,4 @@ def run_junit_test(
     tgt = rule_runner.get_target(
         Address(spec_path="", target_name=target_name, relative_file_path=relative_file_path)
     )
-    return rule_runner.request(TestResult, [JavaTestFieldSet.create(tgt)])
+    return rule_runner.request(TestResult, [JunitTestFieldSet.create(tgt)])