/*

 * Copyright (c) 2016, 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.

 */

import java.util.regex.Pattern;

import static java.util.Objects.requireNonNull;

//

// A set of testing utility functions

//

public final class TestKit {

    private TestKit() { }

    public static void assertNotThrows(ThrowingProcedure code) {

        requireNonNull(code, "code");

        assertNotThrows(() -> {

            code.run();

            return null;

        });

    }

    public static <V> V assertNotThrows(ThrowingFunction<V> code) {

        requireNonNull(code, "code");

        try {

            return code.run();

        } catch (Throwable t) {

            throw new RuntimeException("Expected to run normally, but threw "

                    + t.getClass().getCanonicalName(), t);

        }

    }

    public static <T extends Throwable> T assertThrows(Class<? extends T> clazz,

                                                       ThrowingProcedure code) {

        requireNonNull(clazz, "clazz");

        requireNonNull(code, "code");

        try {

            code.run();

        } catch (Throwable t) {

            if (clazz.isInstance(t)) {

                return clazz.cast(t);

            }

            throw new RuntimeException("Expected to catch an exception of type "

                    + clazz.getCanonicalName() + ", but caught "

                    + t.getClass().getCanonicalName(), t);

        }

        throw new RuntimeException("Expected to catch an exception of type "

                + clazz.getCanonicalName() + ", but caught nothing");

    }

    public interface ThrowingProcedure {

        void run() throws Throwable;

    }

    public interface ThrowingFunction<V> {

        V run() throws Throwable;

    }

    // The rationale behind asking for a regex is to not pollute variable names

    // space in the scope of assertion: if it's something as simple as checking

    // a message, we can do it inside

    public static <T extends Throwable> T assertThrows(Class<? extends T> clazz,

                                                       String messageRegex,

                                                       ThrowingProcedure code) {

        requireNonNull(messageRegex, "messagePattern");

        T t = assertThrows(clazz, code);

        String m = t.getMessage();

        if (m == null) {

            throw new RuntimeException(String.format(

                    "Expected exception message to match the regex '%s', " +

                            "but the message was null", messageRegex), t);

        }

        if (!Pattern.matches(messageRegex, m)) {

            throw new RuntimeException(String.format(

                    "Expected exception message to match the regex '%s', " +

                            "actual message: %s", messageRegex, m), t);

        }

        return t;

    }

}