gazelle: Standalone tests depend on their test libraries (#241)

java/gazelle/generate.go

@@ -203,7 +203,7 @@ func (l javaLang) GenerateRules(args language.GenerateArgs) language.GenerateRes
 		libName := filepath.Base(args.Rel)
 		if testHelperJavaClasses.Contains(m) {
 			isTestOnly = true
-			libName += "-test-lib"
+			libName = testHelperLibname(libName)
 		}
 		l.generateJavaBinary(args.File, m, libName, isTestOnly, &res)
 	}
@@ -235,7 +235,7 @@ func (l javaLang) GenerateRules(args language.GenerateArgs) language.GenerateRes
 		case "file":
 			for _, tf := range testJavaFiles.SortedSlice() {
 				extraAttributes := separateTestJavaFiles[tf]
-				l.generateJavaTest(args.File, args.Rel, cfg.MavenRepositoryName(), tf, isModule, testJavaImportsWithHelpers, extraAttributes, &res)
+				l.generateJavaTest(args.File, args.Rel, cfg.MavenRepositoryName(), tf, isModule, testJavaImportsWithHelpers, nil, extraAttributes, &res)
 			}
 
 		case "suite":
@@ -274,7 +274,11 @@ func (l javaLang) GenerateRules(args language.GenerateArgs) language.GenerateRes
 				sortedSeparateTestJavaFiles.Add(src)
 			}
 			for _, src := range sortedSeparateTestJavaFiles.SortedSlice() {
-				l.generateJavaTest(args.File, args.Rel, cfg.MavenRepositoryName(), src, isModule, testJavaImportsWithHelpers, separateTestJavaFiles[src], &res)
+				var testHelperDep *string
+				if testHelperJavaFiles.Len() > 0 {
+					testHelperDep = ptr(testHelperLibname(suiteName))
+				}
+				l.generateJavaTest(args.File, args.Rel, cfg.MavenRepositoryName(), src, isModule, testJavaImportsWithHelpers, testHelperDep, separateTestJavaFiles[src], &res)
 			}
 		}
 	}
@@ -484,7 +488,7 @@ func (l javaLang) generateJavaBinary(file *rule.File, m types.ClassName, libName
 	})
 }
 
-func (l javaLang) generateJavaTest(file *rule.File, pathToPackageRelativeToBazelWorkspace string, mavenRepositoryName string, f javaFile, includePackageInName bool, imports *sorted_set.SortedSet[types.PackageName], extraAttributes map[string]bzl.Expr, res *language.GenerateResult) {
+func (l javaLang) generateJavaTest(file *rule.File, pathToPackageRelativeToBazelWorkspace string, mavenRepositoryName string, f javaFile, includePackageInName bool, imports *sorted_set.SortedSet[types.PackageName], depOnTestHelpers *string, extraAttributes map[string]bzl.Expr, res *language.GenerateResult) {
 	className := f.ClassName()
 	fullyQualifiedTestClass := className.FullyQualifiedClassName()
 	var testName string
@@ -516,6 +520,10 @@ func (l javaLang) generateJavaTest(file *rule.File, pathToPackageRelativeToBazel
 	r.SetAttr("test_class", fullyQualifiedTestClass)
 	r.SetPrivateAttr(packagesKey, []types.ResolvableJavaPackage{*types.NewResolvableJavaPackage(f.pkg, true, false)})
 
+	if depOnTestHelpers != nil {
+		r.SetAttr("deps", []string{*depOnTestHelpers})
+	}
+
 	if runtimeDeps.Len() != 0 {
 		r.SetAttr("runtime_deps", labelsToStrings(runtimeDeps.SortedSlice()))
 	}
@@ -618,3 +626,11 @@ func labelsToStrings(labels []label.Label) []string {
 	}
 	return out
 }
+
+func testHelperLibname(targetName string) string {
+	return targetName + "-test-lib"
+}
+
+func ptr[T any](v T) *T {
+	return &v
+}

java/gazelle/generate_test.go

@@ -135,7 +135,7 @@ func TestSingleJavaTestFile(t *testing.T) {
 			var res language.GenerateResult
 
 			l := newTestJavaLang(t)
-			l.generateJavaTest(nil, "", "maven", f, tc.includePackageInName, stringsToPackageNames(tc.importedPackages), nil, &res)
+			l.generateJavaTest(nil, "", "maven", f, tc.includePackageInName, stringsToPackageNames(tc.importedPackages), nil, nil, &res)
 
 			require.Len(t, res.Gen, 1, "want 1 generated rule")
 

java/gazelle/testdata/attribute_setting/src/test/com/hastestutil/BUILD.out

@@ -0,0 +1,36 @@
+load("@contrib_rules_jvm//java:defs.bzl", "java_junit5_test", "java_test_suite")
+
+java_test_suite(
+    name = "hastestutil",
+    srcs = [
+        "RandomNumberGenerator.java",
+        "ReliableTest.java",
+    ],
+    runner = "junit5",
+    runtime_deps = [
+        "@maven//:org_junit_jupiter_junit_jupiter_engine",
+        "@maven//:org_junit_platform_junit_platform_launcher",
+        "@maven//:org_junit_platform_junit_platform_reporting",
+    ],
+    deps = [
+        "//src/main/com/example/annotation",
+        "@maven//:org_junit_jupiter_junit_jupiter_api",
+    ],
+)
+
+java_junit5_test(
+    name = "RandomTest",
+    srcs = ["RandomTest.java"],
+    flaky = True,
+    test_class = "com.example.hastestutil.RandomTest",
+    runtime_deps = [
+        "@maven//:org_junit_jupiter_junit_jupiter_engine",
+        "@maven//:org_junit_platform_junit_platform_launcher",
+        "@maven//:org_junit_platform_junit_platform_reporting",
+    ],
+    deps = [
+        ":hastestutil-test-lib",
+        "//src/main/com/example/annotation",
+        "@maven//:org_junit_jupiter_junit_jupiter_api",
+    ],
+)

java/gazelle/testdata/attribute_setting/src/test/com/hastestutil/RandomNumberGenerator.java

@@ -0,0 +1,8 @@
+package com.example.hastestutil;
+
+public class RandomNumberGenerator {
+    public static int generateNumberLessThanTwo() {
+        Random random = new Random();
+        return random.nextInt(2);
+    }
+}

java/gazelle/testdata/attribute_setting/src/test/com/hastestutil/RandomTest.java

@@ -0,0 +1,17 @@
+package com.example.hastestutil;
+
+import com.example.annotation.FlakyTest;
+import org.junit.jupiter.api.Test;
+
+import java.util.Random;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+@FlakyTest
+public class RandomTest {
+  @Test
+  public void unreliableTest() {
+    int r = RandomNumberGenerator.generateNumberLessThanTwo();
+    assertEquals(r, 0);
+  }
+}

java/gazelle/testdata/attribute_setting/src/test/com/hastestutil/ReliableTest.java

@@ -0,0 +1,15 @@
+package com.example.hastestutil;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Random;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class ReliableTest {
+  @Test
+  public void reliableTest() {
+    int r = RandomNumberGenerator.generateNumberLessThanTwo();
+    assertTrue(r < 2);
+  }
+}