Introduce MoreASTHelpersTest

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/util/MoreASTHelpersTest.java

@@ -0,0 +1,72 @@
+package tech.picnic.errorprone.bugpatterns.util;
+
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+import static java.util.stream.Collectors.joining;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.CompilationTestHelper;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
+import com.google.errorprone.matchers.Description;
+import com.sun.source.tree.MethodTree;
+import org.junit.jupiter.api.Test;
+
+final class MoreASTHelpersTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(TestChecker.class, getClass())
+        .addSourceLines(
+            "/A.java",
+            "class A {",
+            "  // BUG: Diagnostic contains: foo: (1, true), bar: (2, true), baz: (0, false)",
+            "  void foo() {}",
+            "",
+            "  // BUG: Diagnostic contains: (1, true), bar: (2, true), baz: (0, false)",
+            "  void bar() {}",
+            "",
+            "  // BUG: Diagnostic contains: foo: (1, true), bar: (2, true), baz: (0, false)",
+            "  void bar(int i) {}",
+            "",
+            "  static class B {",
+            "    // BUG: Diagnostic contains: (0, false), bar: (1, true), baz: (1, true)",
+            "    void bar() {}",
+            "",
+            "    // BUG: Diagnostic contains: (0, false), bar: (1, true), baz: (1, true)",
+            "    void baz() {}",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  /**
+   * A {@link BugChecker} that flags methods with a diagnostics message that indicates, for each
+   * method, the result of calling the methods from {@link MoreASTHelpers}.
+   */
+  @BugPattern(
+      summary = "Interacts with `MoreASTHelpersTest` for testing purposes",
+      severity = ERROR)
+  public static final class TestChecker extends BugChecker implements MethodTreeMatcher {
+    private static final long serialVersionUID = 1L;
+
+    private static final ImmutableSet<String> METHOD_NAMES = ImmutableSet.of("foo", "bar", "baz");
+
+    @Override
+    public Description matchMethod(MethodTree tree, VisitorState state) {
+      return buildDescription(tree)
+          .setMessage(
+              METHOD_NAMES.stream()
+                  .map(methodName -> String.join(": ", methodName, collectData(methodName, state)))
+                  .collect(joining(", ")))
+          .build();
+    }
+
+    private static String collectData(String methodName, VisitorState state) {
+      return String.format(
+          "(%s, %s)",
+          MoreASTHelpers.findMethods(methodName, state).size(),
+          MoreASTHelpers.isMethodInEnclosingClass(methodName, state));
+    }
+  }
+}