core: add framework for internal tests

jadx-core/src/main/java/jadx/api/Decompiler.java

@@ -191,4 +191,8 @@ public final class Decompiler {
 			LOG.error("Process class error", e);
 		}
 	}
+
+	RootNode getRoot() {
+		return root;
+	}
 }

jadx-core/src/test/java/jadx/api/InternalJadxTest.java

+package jadx.api;
+
+import jadx.core.Jadx;
+import jadx.core.dex.nodes.ClassNode;
+import jadx.core.dex.nodes.MethodNode;
+import jadx.core.dex.visitors.DepthTraverser;
+import jadx.core.dex.visitors.IDexTreeVisitor;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.net.URL;
+import java.util.List;
+import java.util.jar.JarEntry;
+import java.util.jar.JarOutputStream;
+
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.fail;
+
+public abstract class InternalJadxTest {
+
+	public ClassNode getClassNode(Class clazz) {
+		try {
+			File temp = getJarForClass(clazz);
+
+			Decompiler d = new Decompiler();
+			try {
+				d.loadFile(temp);
+				assertEquals(d.getClasses().size(), 1);
+			} catch (Exception e) {
+				fail(e.getMessage());
+			} finally {
+				temp.delete();
+			}
+
+			List<ClassNode> classes = d.getRoot().getClasses(false);
+			ClassNode cls = classes.get(0);
+
+			assertEquals(cls.getFullName(), clazz.getName());
+
+			cls.load();
+			List<IDexTreeVisitor> passes = Jadx.getPassesList(new DefaultJadxArgs(), null);
+			for (IDexTreeVisitor visitor : passes) {
+				DepthTraverser.visit(visitor, cls);
+			}
+			return cls;
+		} catch (Exception e) {
+			fail(e.getMessage());
+			return null;
+		}
+	}
+
+	protected MethodNode getMethod(ClassNode cls, String method) {
+		for (MethodNode mth : cls.getMethods()) {
+			if (mth.getName().equals(method)) {
+				return mth;
+			}
+		}
+		fail("Method not found " + method + " in class " + cls);
+		return null;
+	}
+
+	public File getJarForClass(Class<?> cls) throws IOException {
+		File classFile = getClassFile(cls);
+		String shortClsFileName = cls.getName().replace('.', '/') + ".class";
+
+		File temp = File.createTempFile("jadx-tmp-", System.nanoTime() + ".jar");
+		JarOutputStream jo = new JarOutputStream(new FileOutputStream(temp));
+		add(classFile, shortClsFileName, jo);
+		jo.close();
+		temp.deleteOnExit();
+		return temp;
+	}
+
+	private File getClassFile(Class<?> cls) {
+		String path = cutPackage(cls) + ".class";
+		URL resource = cls.getResource(path);
+		if (resource == null) {
+			throw new AssertionError("Class file not found: " + path);
+		}
+		if (!"file".equalsIgnoreCase(resource.getProtocol())) {
+			throw new IllegalStateException("Class is not stored in a file.");
+		}
+		return new File(resource.getPath());
+	}
+
+	private String cutPackage(Class<?> cls) {
+		String longName = cls.getName();
+		String pkg = cls.getPackage().getName();
+		return longName.substring(pkg.length() + 1, longName.length());
+	}
+
+	private void add(File source, String entryName, JarOutputStream target) throws IOException {
+		BufferedInputStream in = null;
+		try {
+			JarEntry entry = new JarEntry(entryName);
+			entry.setTime(source.lastModified());
+			target.putNextEntry(entry);
+			in = new BufferedInputStream(new FileInputStream(source));
+
+			byte[] buffer = new byte[1024];
+			while (true) {
+				int count = in.read(buffer);
+				if (count == -1)
+					break;
+				target.write(buffer, 0, count);
+			}
+			target.closeEntry();
+		} finally {
+			if (in != null)
+				in.close();
+		}
+	}
+}

jadx-core/src/test/java/jadx/api/TestFieldIncrement.java

+package jadx.api;
+
+import jadx.core.dex.instructions.ArithNode;
+import jadx.core.dex.instructions.ArithOp;
+import jadx.core.dex.instructions.InsnType;
+import jadx.core.dex.nodes.ClassNode;
+import jadx.core.dex.nodes.InsnNode;
+import jadx.core.dex.nodes.MethodNode;
+
+import java.util.List;
+
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.junit.Assert.assertThat;
+
+public class TestFieldIncrement extends InternalJadxTest {
+
+	public static class TestCls {
+		public int field = 1;
+
+		public void method() {
+			field++;
+		}
+	}
+
+	@Test
+	public void test() {
+		ClassNode cls = getClassNode(TestCls.class);
+		MethodNode mth = getMethod(cls, "method");
+
+		List<InsnNode> insns = mth.getBasicBlocks().get(0).getInstructions();
+		assertEquals(insns.size(), 1);
+		InsnNode insnNode = insns.get(0);
+		assertEquals(InsnType.ARITH, insnNode.getType());
+		assertEquals(ArithOp.ADD, ((ArithNode) insnNode).getOp());
+
+		assertThat(cls.getCode().toString(), containsString("field++;"));
+	}
+}