transcendental-lisp/acceptance/fixture/LispInterpreterFixture.java

package fixture;

import java.io.*;

import interpreter.*;

public class LispInterpreterFixture {

    private ByteArrayOutputStream outputStream;
    private LispInterpreter interpreter;

    public LispInterpreterFixture() throws IOException {
        this.outputStream = new ByteArrayOutputStream();
        this.interpreter = buildInterpreter();
    }

    private LispInterpreter buildInterpreter() {
        LispInterpreterBuilder builder = LispInterpreterBuilderImpl.getInstance();
        builder.setOutput(new PrintStream(outputStream));
        builder.setErrorOutput(new PrintStream(outputStream));
        builder.setNotInteractive();
        builder.setTerminationFunction(() -> System.exit(0));
        builder.setErrorTerminationFunction(() -> System.exit(1));

        return builder.build();
    }

    public String evaluate(String input) throws IOException {
        interpreter.setInput(new ByteArrayInputStream(input.getBytes()), "fitnesse");
        interpreter.interpret();
        String output = outputStream.toString();
        outputStream.reset();

        return output.trim();
    }

}