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Preserve CharSequence assertions in sequenced collections #1095

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1dd7ed3
Preserve string-specific sequenced assertions
martinfrancois Aug 12, 2026
2be5cd7
Extract object-equality assertion names into a named constant
martinfrancois Aug 16, 2026
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44 changes: 44 additions & 0 deletions ...main/java/org/openrewrite/java/testing/assertj/SimplifySequencedCollectionAssertions.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
package org.openrewrite.java.testing.assertj;

import lombok.Getter;
import org.openrewrite.Cursor;
import org.openrewrite.ExecutionContext;
import org.openrewrite.Preconditions;
import org.openrewrite.Recipe;
Expand All @@ -27,9 +28,17 @@
import org.openrewrite.java.search.UsesMethod;
import org.openrewrite.java.tree.Expression;
import org.openrewrite.java.tree.J;
import org.openrewrite.java.tree.TypeUtils;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class SimplifySequencedCollectionAssertions extends Recipe {

// Object-equality assertions come from AbstractAssert, so they do not depend on CharSequence behavior
private static final Set<String> OBJECT_EQUALITY_ASSERTIONS = new HashSet<>(Arrays.asList("isEqualTo", "isNotEqualTo"));

private static final MethodMatcher ASSERT_THAT_MATCHER = new MethodMatcher("org.assertj.core.api.Assertions assertThat(..)");
private static final MethodMatcher GET_FIRST_MATCHER = new MethodMatcher("java.util.* getFirst()");
private static final MethodMatcher GET_LAST_MATCHER = new MethodMatcher("java.util.* getLast()");
Expand Down Expand Up @@ -63,16 +72,51 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu
if (arg instanceof J.MethodInvocation) {
// Check if the method is getFirst() or getLast() on a SequencedCollection
if (GET_FIRST_MATCHER.matches(arg)) {
if (usesCharSequenceSpecificAssertion((J.MethodInvocation) arg)) {
return mi;
}
return assertThat(mi, (J.MethodInvocation) arg, "first", ctx);
}
if (GET_LAST_MATCHER.matches(arg)) {
if (usesCharSequenceSpecificAssertion((J.MethodInvocation) arg)) {
return mi;
}
return assertThat(mi, (J.MethodInvocation) arg, "last", ctx);
}
}

return mi;
}

private boolean usesCharSequenceSpecificAssertion(J.MethodInvocation elementAccess) {
if (!TypeUtils.isAssignableTo("java.lang.CharSequence", elementAccess.getType())) {
return false;
}
J.MethodInvocation selected = getCursor().getValue();
Cursor assertionCursor = getCursor().getParentTreeCursor();
while (assertionCursor != null && assertionCursor.getValue() instanceof J.MethodInvocation) {
J.MethodInvocation assertion = assertionCursor.getValue();
if (!(assertion.getSelect() instanceof J.MethodInvocation) ||
!selected.getId().equals(((J.MethodInvocation) assertion.getSelect()).getId())) {
break;
}
if (isCharSequenceSpecificAssertion(assertion)) {
return true;
}
selected = assertion;
assertionCursor = assertionCursor.getParentTreeCursor();
}
return false;
}

private boolean isCharSequenceSpecificAssertion(J.MethodInvocation assertion) {
if (OBJECT_EQUALITY_ASSERTIONS.contains(assertion.getSimpleName())) {
return false;
}
return assertion.getMethodType() != null && TypeUtils.isAssignableTo(
"org.assertj.core.api.AbstractCharSequenceAssert", assertion.getMethodType().getDeclaringType());
}

private J.MethodInvocation assertThat(J.MethodInvocation mi, J.MethodInvocation argMethod, String dedicatedAssertion, ExecutionContext ctx) {
return JavaTemplate.builder("assertThat(#{any(java.lang.Iterable)})." + dedicatedAssertion + "()")
.staticImports("org.assertj.core.api.Assertions.assertThat")
Expand Down
66 changes: 64 additions & 2 deletions .../java/org/openrewrite/java/testing/assertj/SimplifySequencedCollectionAssertionsTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -127,8 +127,70 @@ class MyTest {
void testMethod() {
List<String> list = List.of("a", "b", "c");
assertThat(list).last().isNotNull();
assertThat(list).first().isNotEmpty();
assertThat(list).last().contains("c");
assertThat(list.getFirst()).isNotEmpty();
assertThat(list.getLast()).contains("c");
}
}
"""
)
);
}

@Test
void retainsCharSequenceSpecificAssertions() {
rewriteRun(
//language=java
java(
"""
import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;

class FirstElementTest {
void verify(List<String> command) {
assertThat(command.getFirst()).endsWith("setsid");
}
}
"""
),
//language=java
java(
"""
import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;

class NullableElementTest {
void verify(List<String> values) {
assertThat(values.getFirst()).usingComparator(String.CASE_INSENSITIVE_ORDER).isNull();
}
}
"""
),
//language=java
java(
"""
import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;

class ConfiguredAssertionTest {
void verify(List<String> values) {
assertThat(values.getFirst()).as("value").startsWith("a");
}
}
"""
),
//language=java
java(
"""
import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;

class CharSequenceElementTest {
void verify(List<StringBuilder> values) {
assertThat(values.getFirst()).startsWith("a");
}
}
"""
Expand Down
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