Migrate from JUnit 4 to JUnit 5 to resolve deprecation warnings (#897)

- Update build.sbt to use JUnit 5 dependencies (jupiter + vintage)
- Replace JUnit 4 imports with JUnit 5 equivalents
- Convert @test(expected=Exception.class) to assertThrows()
- Update @before to @beforeeach annotation
- Replace deprecated org.junit.Assert.assertThat with Hamcrest assertThat
- Maintain backward compatibility with JUnit Vintage engine

Fixes all JUnit deprecation warnings in msgpack-jackson tests.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <[email protected]>

Author: xerial

build.sbt

@@ -46,7 +46,8 @@ val buildSettings = Seq[Setting[_]](
   Test / compile := ((Test / compile) dependsOn (Test / jcheckStyle)).value
 )
 
-val junitInterface = "com.github.sbt" % "junit-interface" % "0.13.3" % "test"
+val junitJupiter = "org.junit.jupiter" % "junit-jupiter" % "5.11.4" % "test"
+val junitVintage = "org.junit.vintage" % "junit-vintage-engine" % "5.11.4" % "test"
 
 // Project settings
 lazy val root = Project(id = "msgpack-java", base = file("."))
@@ -83,7 +84,8 @@ lazy val msgpackCore = Project(id = "msgpack-core", base = file("msgpack-core"))
     Test / fork := true,
     libraryDependencies ++= Seq(
       // msgpack-core should have no external dependencies
-      junitInterface,
+      junitJupiter,
+      junitVintage,
       "org.wvlet.airframe" %% "airframe-json" % AIRFRAME_VERSION % "test",
       "org.wvlet.airframe" %% "airspec"       % AIRFRAME_VERSION % "test",
       // Add property testing support with forAll methods
@@ -110,7 +112,8 @@ lazy val msgpackJackson =
       ),
       libraryDependencies ++= Seq(
         "com.fasterxml.jackson.core" % "jackson-databind" % "2.18.2",
-        junitInterface,
+        junitJupiter,
+        junitVintage,
         "org.apache.commons" % "commons-math3" % "3.6.1" % "test"
       ),
       testOptions += Tests.Argument(TestFrameworks.JUnit, "-v")

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackDataformatForFieldIdTest.java

@@ -33,9 +33,9 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.LinkedHashMap;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public class MessagePackDataformatForFieldIdTest
 {

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackDataformatForPojoTest.java

@@ -16,17 +16,17 @@
 package org.msgpack.jackson.dataformat;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
 import java.nio.charset.Charset;
 
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.CoreMatchers.containsString;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.hamcrest.MatcherAssert.assertThat;
 
 public class MessagePackDataformatForPojoTest
         extends MessagePackDataformatTestBase

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackFactoryTest.java

@@ -23,7 +23,7 @@
 import com.fasterxml.jackson.databind.AnnotationIntrospector;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.msgpack.core.MessagePack;
 
 import java.io.IOException;
@@ -35,8 +35,8 @@
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.CoreMatchers.nullValue;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.hamcrest.MatcherAssert.assertThat;
 
 public class MessagePackFactoryTest
         extends MessagePackDataformatTestBase

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackGeneratorTest.java

@@ -24,7 +24,7 @@
 import com.fasterxml.jackson.databind.SerializerProvider;
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import com.fasterxml.jackson.databind.module.SimpleModule;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.msgpack.core.ExtensionTypeHeader;
 import org.msgpack.core.MessagePack;
 import org.msgpack.core.MessageUnpacker;
@@ -53,13 +53,14 @@
 import java.util.concurrent.TimeUnit;
 
 import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.hamcrest.MatcherAssert.assertThat;
 
 public class MessagePackGeneratorTest
         extends MessagePackDataformatTestBase
@@ -349,7 +350,7 @@ public void testBigDecimal()
         }
     }
 
-    @Test(expected = IOException.class)
+    @Test
     public void testEnableFeatureAutoCloseTarget()
             throws IOException
     {
@@ -358,7 +359,9 @@ public void testEnableFeatureAutoCloseTarget()
         ObjectMapper objectMapper = new ObjectMapper(messagePackFactory);
         List<Integer> integers = Arrays.asList(1);
         objectMapper.writeValue(out, integers);
-        objectMapper.writeValue(out, integers);
+        assertThrows(IOException.class, () -> {
+            objectMapper.writeValue(out, integers);
+        });
     }
 
     @Test

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackMapperTest.java

@@ -16,14 +16,14 @@
 package org.msgpack.jackson.dataformat;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.fail;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
 
 public class MessagePackMapperTest
 {

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackParserTest.java

@@ -27,7 +27,7 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
 import com.fasterxml.jackson.databind.module.SimpleModule;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.msgpack.core.MessagePack;
 import org.msgpack.core.MessagePacker;
 import org.msgpack.value.ExtensionValue;
@@ -52,10 +52,11 @@
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.core.Is.is;
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 public class MessagePackParserTest
         extends MessagePackDataformatTestBase
@@ -450,7 +451,7 @@ public void setup(File f)
         return tempFile;
     }
 
-    @Test(expected = IOException.class)
+    @Test
     public void testEnableFeatureAutoCloseSource()
             throws Exception
     {
@@ -459,7 +460,9 @@ public void testEnableFeatureAutoCloseSource()
         FileInputStream in = new FileInputStream(tempFile);
         ObjectMapper objectMapper = new ObjectMapper(factory);
         objectMapper.readValue(in, new TypeReference<List<Integer>>() {});
-        objectMapper.readValue(in, new TypeReference<List<Integer>>() {});
+        assertThrows(IOException.class, () -> {
+            objectMapper.readValue(in, new TypeReference<List<Integer>>() {});
+        });
     }
 
     @Test

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/TimestampExtensionModuleTest.java

@@ -16,8 +16,8 @@
 package org.msgpack.jackson.dataformat;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.msgpack.core.MessagePack;
 import org.msgpack.core.MessagePacker;
 import org.msgpack.core.MessageUnpacker;
@@ -26,7 +26,7 @@
 import java.io.IOException;
 import java.time.Instant;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public class TimestampExtensionModuleTest
 {
@@ -46,7 +46,7 @@ private static class TripleInstants
         public Instant c;
     }
 
-    @Before
+    @BeforeEach
     public void setUp()
             throws Exception
     {

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/benchmark/MessagePackDataformatHugeDataBenchmarkTest.java

@@ -19,7 +19,7 @@
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.msgpack.jackson.dataformat.MessagePackFactory;
 
 import java.io.File;

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/benchmark/MessagePackDataformatPojoBenchmarkTest.java

@@ -17,7 +17,7 @@
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.msgpack.jackson.dataformat.MessagePackFactory;
 import static org.msgpack.jackson.dataformat.MessagePackDataformatTestBase.NormalPojo;
 import static org.msgpack.jackson.dataformat.MessagePackDataformatTestBase.Suit;