Add TestCallStackUtils

src/test/java/org/apache/commons/pool2/impl/TestCallStackUtils.java

@@ -0,0 +1,57 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.pool2.impl;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link CallStackUtils}.
+ */
+public class TestCallStackUtils {
+
+    private static final String MESSAGE_FORMAT = "'Timestamp:' yyyy-MM-dd HH:mm:ss Z";
+
+    private void assertNewCallStack(final CallStack callStack) {
+        callStack.fillInStackTrace();
+        final StringWriter out = new StringWriter();
+        callStack.printStackTrace(new PrintWriter(out));
+        assertFalse(out.toString().isEmpty());
+        callStack.clear();
+        out.getBuffer().setLength(0);
+        callStack.printStackTrace(new PrintWriter(out));
+        assertTrue(out.toString().isEmpty());
+    }
+
+    @Test
+    public void testNewCallStack2() {
+        assertNewCallStack(CallStackUtils.newCallStack(MESSAGE_FORMAT, false));
+        assertNewCallStack(CallStackUtils.newCallStack(MESSAGE_FORMAT, true));
+    }
+
+    @Test
+    public void testNewCallStack3() {
+        assertNewCallStack(CallStackUtils.newCallStack(MESSAGE_FORMAT, false, false));
+        assertNewCallStack(CallStackUtils.newCallStack(MESSAGE_FORMAT, false, true));
+    }
+}