test: switch with fallthrough cases (#826)

jadx-core/src/main/java/jadx/core/dex/instructions/SwitchNode.java

@@ -3,6 +3,7 @@ package jadx.core.dex.instructions;
 import java.util.Arrays;
 import java.util.List;
 
+import jadx.core.codegen.CodeWriter;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.nodes.BlockNode;
 import jadx.core.dex.nodes.InsnNode;
@@ -110,15 +111,13 @@ public class SwitchNode extends TargetInsnNode {
 
 	@Override
 	public String toString() {
-		StringBuilder targ = new StringBuilder();
-		targ.append('[');
+		StringBuilder sb = new StringBuilder();
+		sb.append(super.toString());
 		for (int i = 0; i < targets.length; i++) {
-			targ.append(InsnUtils.formatOffset(targets[i]));
-			if (i < targets.length - 1) {
-				targ.append(", ");
-			}
+			sb.append("  case ").append(keys[i])
+					.append(": goto ").append(InsnUtils.formatOffset(targets[i]));
+			sb.append(CodeWriter.NL);
 		}
-		targ.append(']');
-		return super.toString() + " k:" + Arrays.toString(keys) + " t:" + targ;
+		return sb.toString();
 	}
 }

jadx-core/src/test/java/jadx/tests/integration/switches/TestSwitchFallThrough.java

@@ -0,0 +1,54 @@
+package jadx.tests.integration.switches;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.NotYetImplemented;
+import jadx.tests.api.IntegrationTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestSwitchFallThrough extends IntegrationTest {
+
+	public static class TestCls {
+		public int r;
+
+		public void test(int a) {
+			int i = 10;
+			switch (a) {
+				case 1:
+					i = 1000;
+					// fallthrough
+				case 2:
+					r = i;
+					break;
+
+				default:
+					r = -1;
+					break;
+			}
+			r *= 2;
+			System.out.println("in: " + a + ", out: " + r);
+		}
+
+		public int testWrap(int a) {
+			r = 0;
+			test(a);
+			return r;
+		}
+
+		public void check() {
+			assertThat(testWrap(1)).isEqualTo(2000);
+			assertThat(testWrap(2)).isEqualTo(20);
+			assertThat(testWrap(0)).isEqualTo(-2);
+		}
+	}
+
+	@NotYetImplemented("switch fallthrough")
+	@Test
+	public void test() {
+		assertThat(getClassNode(TestCls.class))
+				.code()
+				.containsOnlyOnce("switch");
+		// code correctness checks done in 'check' method
+	}
+}