8222430: Add tests for ElementKind predicates

Backport-of: 4a9f761

test/langtools/tools/javac/processing/model/element/TestElementKindPredicates.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8222430
+ * @summary Test various predicates of ElementKind.
+ */
+
+import java.util.Set;
+import java.util.function.Predicate;
+import javax.lang.model.element.ElementKind;
+
+/**
+ * Test the isClass, isField, and isInterface predicates of ElementKind.
+ */
+public class TestElementKindPredicates {
+    public static void main(String... args) {
+        Set<ElementKind> ALL_KINDS = Set.of(ElementKind.values());
+
+        // isClass: Returns true if this is a kind of class: either CLASS or ENUM.
+        test(ALL_KINDS,
+             (ElementKind k) -> Set.of(ElementKind.CLASS,
+                                       ElementKind.ENUM).contains(k),
+             (ElementKind k) -> k.isClass(), "isClass");
+
+        // isField: Returns true if this is a kind of field: either FIELD or ENUM_CONSTANT.
+        test(ALL_KINDS,
+             (ElementKind k) -> Set.of(ElementKind.FIELD,
+                                       ElementKind.ENUM_CONSTANT).contains(k),
+             (ElementKind k) -> k.isField(), "isField");
+
+        // isInterface: Returns true if this is a kind of interface: either INTERFACE or ANNOTATION_TYPE.
+        test(ALL_KINDS,
+             (ElementKind k) -> Set.of(ElementKind.INTERFACE,
+                                       ElementKind.ANNOTATION_TYPE).contains(k),
+             (ElementKind k) -> k.isInterface(), "isInterface");
+    }
+
+    private static void test(Set<ElementKind> kinds,
+                             Predicate<ElementKind> expectedPred,
+                             Predicate<ElementKind> actualPred,
+                             String errorMessage) {
+        for(ElementKind kind : kinds) {
+            boolean expected = expectedPred.test(kind);
+            boolean actual = actualPred.test(kind);
+
+            if (expected != actual) {
+                throw new RuntimeException("Error testing ElementKind." + errorMessage + "(" +  kind +
+                                           "):\texpected " + expected + "\tgot " + actual);
+            }
+        }
+    }
+}