ExampleProviderRule.java

package de.zalando.toga.provider;

import de.zalando.toga.generator.Generator;
import org.junit.rules.MethodRule;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.Statement;

import java.io.File;
import java.util.regex.Pattern;

public class ExampleProviderRule implements MethodRule {

    private final ExampleProvider exampleProvider;
    private Pattern pattern;
    private String current;

    /**
     * This rule will execute all tests in this class for every example in the specified input folder.
     * @param dir this folder will be searched for json files containing example data.
     * @param pattern the pattern to apply. See {@link ExampleProvider} for details.
     */
    public ExampleProviderRule(final File dir, final Pattern pattern) {
        this.pattern = pattern;
        exampleProvider = new ExampleProvider(dir);
    }

    /**
     * Takes the given json-schema specification file and then invokes a {@link de.zalando.toga.generator.Generator} to
     * create examples in the given example directory. Afterwards the given pattern is used to extract all relevant examples
     * for test execution.
     *
     * @param specification the json-schema file that contains the specification under test
     * @param exampleDirectory the directory to generate the examples to
     * @param pattern the pattern to filter the examples with. See {@link ExampleProvider} for details.
     */
    public ExampleProviderRule(final File specification, final File exampleDirectory, final Pattern pattern) {

        // TODO: make generation of multiple files possible
        Generator generator = new Generator();
        generator.load(specification);
        generator.generate(new File(exampleDirectory, specification.getName()));

        this.pattern = pattern;
        exampleProvider = new ExampleProvider(exampleDirectory);
    }

    public String getExampleJson() {
        return current;
    }

    @Override
    public Statement apply(Statement base, FrameworkMethod method, Object target) {
        return new Statement() {
            @Override
            public void evaluate() throws Throwable {
                for (String input : exampleProvider.getExamples(pattern)) {
                    current = input;
                    base.evaluate();
                }
            }
        };
    }
}