package function.builtin;

import static org.junit.Assert.assertEquals;
import static testutil.TestUtilities.*;

import java.io.*;

import org.junit.*;

import environment.Environment;
import function.ArgumentValidator.*;
import sexpression.*;

public class LOADTester {

    private ByteArrayOutputStream outputStream;

    private void assertPrinted(String expected) {
        assertEquals(expected, outputStream.toString());
    }

    private void assertNothingPrinted() {
        assertPrinted("");
    }

    @Before
    public void setUp() {
        this.outputStream = new ByteArrayOutputStream();
        Environment.getInstance().setErrorOutput(new PrintStream(outputStream));
    }

    @Test
    public void loadGoodFile_ReturnsTAndPrintsNothing() {
        String input = "(load \"test/function/builtin/test-files/load-good.lisp\")";

        assertSExpressionsMatch(Symbol.T, evaluateString(input));
        assertNothingPrinted();
    }

    @Test
    public void loadBadFile_ReturnsNilAndPrintsError() {
        String input = "(load \"test/function/builtin/test-files/load-bad.lisp\")";

        assertSExpressionsMatch(Nil.getInstance(), evaluateString(input));
        assertPrinted("LOAD: expression begins with ')' - line 1, column 1\n");
    }

    @Test
    public void loadNonExistentFile_ReturnsNilAndPrintsError() {
        String input = "(load \"doesNotExist.lisp\")";

        assertSExpressionsMatch(Nil.getInstance(), evaluateString(input));
        assertPrinted("LOAD: could not open 'doesNotExist.lisp'\n");
    }

    @Test(expected = BadArgumentTypeException.class)
    public void testLoadWithBadArgumentType() {
        evaluateString("(load '1)");
    }

    @Test(expected = TooManyArgumentsException.class)
    public void testLoadWithTooManyArguments() {
        evaluateString("(load \"1\" \"2\")");
    }

    @Test(expected = TooFewArgumentsException.class)
    public void testLoadWithTooFewArguments() {
        evaluateString("(load)");
    }

}