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Fix Hamcrest not() unwrap infinite loop and support CoreMatchers #1054

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Merged
timtebeek merged 2 commits into from
Jul 20, 2026
Merged

Fix Hamcrest not() unwrap infinite loop and support CoreMatchers #1054

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a30cba1
Fix infinite loop unwrapping non-Matchers not() in Hamcrest JUnit5 re…
Jammy-Louie Jul 17, 2026
2e95cd7
Migrate CoreMatchers not()/instanceOf()/isA() in Hamcrest JUnit5 recipes
Jammy-Louie Jul 17, 2026
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6 changes: 3 additions & 3 deletions src/main/java/org/openrewrite/java/testing/hamcrest/HamcrestInstanceOfToJUnit5.java
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Original file line number Diff line number Diff line change
Expand Up @@ -38,8 +38,8 @@ public class HamcrestInstanceOfToJUnit5 extends Recipe {
@Getter
final String description = "Migrate from Hamcrest `instanceOf` and `isA` matcher to JUnit5 `assertInstanceOf` assertion.";

private static final MethodMatcher INSTANCE_OF_MATCHER = new MethodMatcher("org.hamcrest.Matchers instanceOf(..)");
private static final MethodMatcher IS_A_MATCHER = new MethodMatcher("org.hamcrest.Matchers isA(..)");
private static final MethodMatcher INSTANCE_OF_MATCHER = new MethodMatcher("org.hamcrest.*Matchers instanceOf(..)");
private static final MethodMatcher IS_A_MATCHER = new MethodMatcher("org.hamcrest.*Matchers isA(..)");
private static final MethodMatcher ASSERT_THAT_MATCHER = new MethodMatcher("org.hamcrest.MatcherAssert assertThat(.., org.hamcrest.Matcher)");

@Override
Expand Down Expand Up @@ -70,7 +70,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation mi, Execution
}

J.MethodInvocation matcherInvocation = (J.MethodInvocation) hamcrestMatcher;
while ("not".equals(matcherInvocation.getSimpleName())) {
while (RemoveNotMatcherVisitor.NOT_MATCHER.matches(matcherInvocation)) {
maybeRemoveImport("org.hamcrest.Matchers.not");
maybeRemoveImport("org.hamcrest.CoreMatchers.not");
matcherInvocation = (J.MethodInvocation) new RemoveNotMatcherVisitor().visit(matcherInvocation, ctx);
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2 changes: 1 addition & 1 deletion src/main/java/org/openrewrite/java/testing/hamcrest/HamcrestMatcherToJUnit5.java
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Expand Up @@ -137,7 +137,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu
J.MethodInvocation matcherInvocation = (J.MethodInvocation) hamcrestMatcher;
maybeRemoveImport("org.hamcrest.MatcherAssert.assertThat");

while ("not".equals(matcherInvocation.getSimpleName())) {
while (RemoveNotMatcherVisitor.NOT_MATCHER.matches(matcherInvocation)) {
maybeRemoveImport("org.hamcrest.Matchers.not");
maybeRemoveImport("org.hamcrest.CoreMatchers.not");
matcherInvocation = (J.MethodInvocation) new RemoveNotMatcherVisitor().visit(matcherInvocation, ctx);
Expand Down
2 changes: 1 addition & 1 deletion src/main/java/org/openrewrite/java/testing/hamcrest/RemoveNotMatcherVisitor.java
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Expand Up @@ -26,7 +26,7 @@
import java.util.Objects;

class RemoveNotMatcherVisitor extends JavaIsoVisitor<ExecutionContext> {
static final MethodMatcher NOT_MATCHER = new MethodMatcher("org.hamcrest.Matchers not(..)");
static final MethodMatcher NOT_MATCHER = new MethodMatcher("org.hamcrest.*Matchers not(..)");

public static boolean getLogicalContext(J.MethodInvocation mi, ExecutionContext ctx) throws InvalidParameterException {
Object msg = ctx.getMessage(mi.toString());
Expand Down
84 changes: 84 additions & 0 deletions src/test/java/org/openrewrite/java/testing/hamcrest/HamcrestInstanceOfToJUnit5Test.java
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Expand Up @@ -16,12 +16,15 @@
package org.openrewrite.java.testing.hamcrest;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.Timeout;
import org.openrewrite.DocumentExample;
import org.openrewrite.InMemoryExecutionContext;
import org.openrewrite.java.JavaParser;
import org.openrewrite.test.RecipeSpec;
import org.openrewrite.test.RewriteTest;

import java.util.concurrent.TimeUnit;

import static org.openrewrite.java.Assertions.java;
import static org.openrewrite.test.TypeValidation.all;

Expand Down Expand Up @@ -81,6 +84,87 @@ void testInstance() {
);
}

@Test
@Timeout(value = 30, unit = TimeUnit.SECONDS, threadMode = Timeout.ThreadMode.SEPARATE_THREAD)
void notFromCoreMatchers() {
//language=java
rewriteRun(
java(
"""
import org.junit.jupiter.api.Test;
import java.util.List;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.CoreMatchers.instanceOf;
import static org.hamcrest.CoreMatchers.not;

class ATest {
private static final List<Integer> list = List.of();
@Test
void testInstance() {
assertThat(list, not(instanceOf(Integer.class)));
}
}
""",
"""
import org.junit.jupiter.api.Test;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertFalse;

class ATest {
private static final List<Integer> list = List.of();
@Test
void testInstance() {
assertFalse(Integer.class.isAssignableFrom(list.getClass()));
}
}
"""
)
);
}

@Test
void instanceOfAndIsAFromCoreMatchers() {
//language=java
rewriteRun(
java(
"""
import org.junit.jupiter.api.Test;
import java.util.List;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.CoreMatchers.instanceOf;
import static org.hamcrest.CoreMatchers.isA;

class ATest {
private static final List<Integer> list = List.of();
@Test
void testInstance() {
assertThat(list, instanceOf(Iterable.class));
assertThat(list, isA(Iterable.class));
}
}
""",
"""
import org.junit.jupiter.api.Test;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertInstanceOf;

class ATest {
private static final List<Integer> list = List.of();
@Test
void testInstance() {
assertInstanceOf(Iterable.class, list);
assertInstanceOf(Iterable.class, list);
}
}
"""
)
);
}

@Test
void assertionsWithReason() {
//language=java
Expand Down
43 changes: 43 additions & 0 deletions src/test/java/org/openrewrite/java/testing/hamcrest/HamcrestMatcherToJUnit5Test.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,12 +16,15 @@
package org.openrewrite.java.testing.hamcrest;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.Timeout;
import org.openrewrite.DocumentExample;
import org.openrewrite.InMemoryExecutionContext;
import org.openrewrite.java.JavaParser;
import org.openrewrite.test.RecipeSpec;
import org.openrewrite.test.RewriteTest;

import java.util.concurrent.TimeUnit;

import static org.openrewrite.java.Assertions.java;
import static org.openrewrite.test.TypeValidation.all;

Expand Down Expand Up @@ -158,6 +161,46 @@ void testEquals() {
);
}

@Test
@Timeout(value = 30, unit = TimeUnit.SECONDS, threadMode = Timeout.ThreadMode.SEPARATE_THREAD)
void notFromCoreMatchers() {
//language=java
rewriteRun(
spec -> spec.typeValidationOptions(all().immutableExecutionContext(false)),
java(
"""
import org.junit.jupiter.api.Test;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.not;

class ATest {
@Test
void testEquals() {
String str1 = "Hello world!";
String str2 = "Hello world!";
assertThat(str1, not(equalTo(str2)));
}
}
""",
"""
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertNotEquals;

class ATest {
@Test
void testEquals() {
String str1 = "Hello world!";
String str2 = "Hello world!";
assertNotEquals(str1, str2);
}
}
"""
)
);
}

@Test
void greaterThan() {
//language=java
Expand Down
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