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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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package com.oracle.truffle.tck;

import com.oracle.truffle.api.vm.TruffleVM;
import java.io.IOException;
import java.util.Random;
import static org.junit.Assert.*;
import org.junit.Test;

/**
 * A collection of tests that can certify language implementation to be compliant with most recent
 * requirements of the Truffle infrastructure and tooling. Subclass, implement abstract methods and
 * include in your test suite.
 */
public abstract class TruffleTCK {
    private TruffleVM tckVM;

    protected TruffleTCK() {
    }

    /**
     * This methods is called before first test is executed. It's purpose is to set a TruffleVM with
     * your language up, so it is ready for testing.
     * {@link TruffleVM#eval(java.lang.String, java.lang.String) Execute} any scripts you need, and
     * prepare global symbols with proper names. The symbols will then be looked up by the
     * infrastructure (using the names provided by you from methods like {@link #plusInt()}) and
     * used for internal testing.
     *
     * @return initialized Truffle virtual machine
     * @throws java.lang.Exception thrown when the VM preparation fails
     */
    protected abstract TruffleVM prepareVM() throws Exception;

    /**
     * Mimetype associated with your language. The mimetype will be passed to
     * {@link TruffleVM#eval(java.lang.String, java.lang.String)} method of the {@link #prepareVM()
     * created TruffleVM}.
     *
     * @return mime type of the tested language
     */
    protected abstract String mimeType();

    /**
     * Name of function which will return value 42 as a number. The return value of the method
     * should be instance of {@link Number} and its {@link Number#intValue()} should return
     * <code>42</code>.
     *
     * @return name of globally exported symbol
     */
    protected abstract String fourtyTwo();

    /**
     * Name of a function that returns <code>null</code>. Truffle languages are encouraged to have
     * their own type representing <code>null</code>, but when such value is returned from
     * {@link TruffleVM#eval}, it needs to be converted to real Java <code>null</code> by sending a
     * foreign access <em>isNull</em> message. There is a test to verify it is really true.
     *
     * @return name of globally exported symbol
     */
    protected abstract String returnsNull();

    /**
     * Name of function to add two integer values together. The symbol will be invoked with two
     * parameters of type {@link Integer} and expects result of type {@link Number} which's
     * {@link Number#intValue()} is equivalent of <code>param1 + param2</code>.
     *
     * @return name of globally exported symbol
     */
    protected abstract String plusInt();

    /**
     * Name of a function in your language to perform a callback to foreign function. Your function
     * should prepare two numbers (18 and 32) and apply them to the function passed in as an
     * argument of your function. It should then add 10 to the returned value and return the result
     * back to its caller.
     *
     * @return name of globally exported symbol
     */
    protected abstract String applyNumbers();

    /**
     * Return a code snippet that is invalid in your language. Its
     * {@link TruffleVM#eval(java.lang.String, java.lang.String) evaluation} should fail and yield
     * an exception.
     *
     * @return code snippet invalid in the tested language
     */
    protected abstract String invalidCode();

    private TruffleVM vm() throws Exception {
        if (tckVM == null) {
            tckVM = prepareVM();
        }
        return tckVM;
    }

    //
    // The tests
    //

    @Test
    public void testFortyTwo() throws Exception {
        TruffleVM.Symbol fourtyTwo = findGlobalSymbol(fourtyTwo());

        Object res = fourtyTwo.invoke(null);

        assert res instanceof Number : "should yield a number, but was: " + res;

        Number n = (Number) res;

        assert 42 == n.intValue() : "The value is 42 =  " + n.intValue();
    }

    @Test
    public void testNull() throws Exception {
        if (getClass() == TruffleTCK.class) {
            return;
        }
        TruffleVM.Symbol retNull = findGlobalSymbol(returnsNull());

        Object res = retNull.invoke(null);

        assertNull("Should yield real Java null", res);
    }

    @Test
    public void testPlusWithInts() throws Exception {
        Random r = new Random();
        int a = r.nextInt(100);
        int b = r.nextInt(100);

        TruffleVM.Symbol plus = findGlobalSymbol(plusInt());

        Object res = plus.invoke(null, a, b);

        assert res instanceof Number : "+ on two ints should yield a number, but was: " + res;

        Number n = (Number) res;

        assert a + b == n.intValue() : "The value is correct: (" + a + " + " + b + ") =  " + n.intValue();
    }

    @Test(expected = IOException.class)
    public void testInvalidTestMethod() throws Exception {
        String mime = mimeType();
        String code = invalidCode();
        Object ret = vm().eval(mime, code);
        fail("Should yield IOException, but returned " + ret);
    }

    @Test
    public void testMaxOrMinValue() throws Exception {
        TruffleVM.Symbol apply = findGlobalSymbol(applyNumbers());

        Object res = apply.invoke(null, new MaxMinObject(true));

        assert res instanceof Number : "result should be a number: " + res;

        Number n = (Number) res;

        assert 42 == n.intValue() : "32 > 18 and plus 10";
    }

    @Test
    public void testMaxOrMinValue2() throws Exception {
        TruffleVM.Symbol apply = findGlobalSymbol(applyNumbers());

        Object res = apply.invoke(null, new MaxMinObject(false));

        assert res instanceof Number : "result should be a number: " + res;

        Number n = (Number) res;

        assert 28 == n.intValue() : "18 < 32 and plus 10";
    }

    private TruffleVM.Symbol findGlobalSymbol(String name) throws Exception {
        TruffleVM.Symbol s = vm().findGlobalSymbol(name);
        assert s != null : "Symbol " + name + " is not found!";
        return s;
    }
}