src/test/java/org/shedlang/compiler/testing/TestProcessRunner.java


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package org.shedlang.compiler.testing;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.stream.Collectors;

public class TestProcessRunner {
    private TestProcessRunner() {
    }

    /**
     * Run a process until it exits, capturing its stdout and stderr.
     */
    public static ExecutionResult runCaptureOutput(List<String> command) throws IOException, InterruptedException {
        var process = new ProcessBuilder()
            .command(command)
            .start();

        var exitCode = process.waitFor();

        try (
            var stdoutReader = process.inputReader(StandardCharsets.UTF_8);
            var stderrReader = process.errorReader(StandardCharsets.UTF_8)
        ) {
            var stdout = stdoutReader.lines().collect(Collectors.joining("\n"));
            var stderr = stderrReader.lines().collect(Collectors.joining("\n"));

            return new ExecutionResult(exitCode, stdout, stderr);
        }
    }
}