org.robolectric/robolectric 4.13: org.robolectric.junit.rules.BackgroundTestRule

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify org.robolectric.junit.rules.BackgroundTestRule in pkg:maven/org.robolectric/robolectric@4.13
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:maven/org.robolectric/robolectric@4.13
Demonstrate these symbols/APIs:
  - org.robolectric.junit.rules.BackgroundTestRule

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"buildCommand":["gradle","--offline","--no-daemon","--no-scan","--console=plain","--project-dir","/work/.csx-vendor/gradle-runner","classes"],"case":{"caseId":"case:sha256:77ffa2463e1983d2d7b1a496352bda2173e06f16847be0d3804bb538b92111b9","contract":["org.robolectric.junit.rules.BackgroundTestRule class file resource is available on classpath with valid Java bytecode magic","BackgroundTestRule bytecode defines constructor and apply method signature for JUnit test execution","BackgroundTestRule bytecode references org.junit.rules.TestRule interface","BackgroundTestRule inner annotation BackgroundTest class file resource is available on classpath with valid Java bytecode magic"],"goal":"verify org.robolectric.junit.rules.BackgroundTestRule in pkg:maven/org.robolectric/robolectric@4.13","kind":"HOW","packages":["pkg:maven/org.robolectric/robolectric@4.13"],"schemaVersion":1,"symbols":["org.robolectric.junit.rules.BackgroundTestRule"]},"contractCommand":["gradle","--offline","--no-daemon","--no-scan","--console=plain","--project-dir","/work/.csx-vendor/gradle-runner","contract"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"maven","language":"java","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"gradle","packageManagerVersion":"8.14.3","runtime":"java","runtimeVersion":"21","schemaVersion":1},"license":"MIT-0","packages":["pkg:maven/org.robolectric/robolectric@4.13"],"schemaVersion":1,"subject":"pkg:maven/org.robolectric/robolectric@4.13","symbols":["org.robolectric.junit.rules.BackgroundTestRule"],"verifierAdapter":"gradle-java@1"}

{
  "schemaVersion": 1,
  "goal": "verify org.robolectric.junit.rules.BackgroundTestRule in pkg:maven/org.robolectric/robolectric@4.13",
  "kind": "HOW",
  "packages": [
    "pkg:maven/org.robolectric/robolectric@4.13"
  ],
  "symbols": [
    "org.robolectric.junit.rules.BackgroundTestRule"
  ]
}

package sample;

public class Sample {
    public static String getSymbol() {
        return "org.robolectric.junit.rules.BackgroundTestRule";
    }

    public static String getPackage() {
        return "pkg:maven/org.robolectric/robolectric@4.13";
    }
}

import sample.Sample;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class Contract {
    private static byte[] readResource(ClassLoader loader, String path) throws Exception {
        try (InputStream in = loader.getResourceAsStream(path)) {
            if (in == null) {
                throw new AssertionError("Resource not found on classpath: " + path);
            }
            return in.readAllBytes();
        }
    }

    private static List<String> parseUtf8Constants(byte[] classBytes) throws Exception {
        DataInputStream dis = new DataInputStream(new ByteArrayInputStream(classBytes));
        int magic = dis.readInt();
        if (magic != 0xCAFEBABE) {
            throw new AssertionError("Invalid class magic header: 0x" + Integer.toHexString(magic));
        }
        int minor = dis.readUnsignedShort();
        int major = dis.readUnsignedShort();
        if (major < 49) {
            throw new AssertionError("Unexpected JVM major version: " + major);
        }

        int cpCount = dis.readUnsignedShort();
        List<String> utf8List = new ArrayList<>();
        int i = 1;
        while (i < cpCount) {
            int tag = dis.readUnsignedByte();
            switch (tag) {
                case 1: // Utf8
                    String str = dis.readUTF();
                    utf8List.add(str);
                    break;
                case 3: // Integer
                case 4: // Float
                    dis.skipBytes(4);
                    break;
                case 5: // Long
                case 6: // Double
                    dis.skipBytes(8);
                    i++; // Long/Double occupies two entries in constant pool
                    break;
                case 7: // Class
                case 8: // String
                case 16: // MethodType
                case 19: // Module
                case 20: // Package
                    dis.skipBytes(2);
                    break;
                case 9: // Fieldref
                case 10: // Methodref
                case 11: // InterfaceMethodref
                case 12: // NameAndType
                case 18: // InvokeDynamic
                    dis.skipBytes(4);
                    break;
                case 15: // MethodHandle
                    dis.skipBytes(3);
                    break;
                default:
                    throw new AssertionError("Unknown constant pool tag: " + tag);
            }
            i++;
        }
        return utf8List;
    }

    public static void main(String[] args) {
        try {
            // 0. Verify sample helper
            if (!"org.robolectric.junit.rules.BackgroundTestRule".equals(Sample.getSymbol())) {
                throw new AssertionError("Sample symbol mismatch: " + Sample.getSymbol());
            }
            if (!"pkg:maven/org.robolectric/robolectric@4.13".equals(Sample.getPackage())) {
                throw new AssertionError("Sample package mismatch: " + Sample.getPackage());
            }

            ClassLoader loader = Contract.class.getClassLoader();

            // 1. Verify BackgroundTestRule class file resource
            String mainClassPath = "org/robolectric/junit/rules/BackgroundTestRule.class";
            byte[] mainBytes = readResource(loader, mainClassPath);
            List<String> mainUtf8 = parseUtf8Constants(mainBytes);

            // 2. Verify BackgroundTestRule bytecode defines constructor and apply method signature
            if (!mainUtf8.contains("<init>")) {
                throw new AssertionError("BackgroundTestRule missing <init> in constant pool");
            }
            if (!mainUtf8.contains("apply")) {
                throw new AssertionError("BackgroundTestRule missing apply in constant pool");
            }
            if (!mainUtf8.contains("(Lorg/junit/runners/model/Statement;Lorg/junit/runner/Description;)Lorg/junit/runners/model/Statement;")) {
                throw new AssertionError("BackgroundTestRule missing apply descriptor in constant pool");
            }

            // 3. Verify BackgroundTestRule bytecode references org.junit.rules.TestRule interface
            if (!mainUtf8.contains("org/junit/rules/TestRule")) {
                throw new AssertionError("BackgroundTestRule does not reference org/junit/rules/TestRule");
            }
            if (!mainUtf8.contains("org/robolectric/junit/rules/BackgroundTestRule")) {
                throw new AssertionError("BackgroundTestRule does not contain its own class name");
            }

            // 4. Verify BackgroundTestRule inner annotation BackgroundTest class file resource
            String annotClassPath = "org/robolectric/junit/rules/BackgroundTestRule$BackgroundTest.class";
            byte[] annotBytes = readResource(loader, annotClassPath);
            List<String> annotUtf8 = parseUtf8Constants(annotBytes);
            if (!annotUtf8.contains("java/lang/annotation/Annotation")) {
                throw new AssertionError("BackgroundTest does not reference java/lang/annotation/Annotation");
            }
            if (!annotUtf8.contains("org/robolectric/junit/rules/BackgroundTestRule$BackgroundTest")) {
                throw new AssertionError("BackgroundTest does not contain its own class name");
            }

            System.out.println("Contract PASS: org.robolectric.junit.rules.BackgroundTestRule contract verified successfully.");
        } catch (Throwable t) {
            t.printStackTrace();
            System.exit(1);
        }
    }
}