Move spliterator invariant checks to CollectionSpliteratorTester

Per review feedback — the spec invariants apply to all spliterators,
not just ConcurrentMap ones, so they belong in the common tester.

Added checks for all four spec-mandated invariants:
- CONCURRENT + SIZED must not coexist
- CONCURRENT + IMMUTABLE must not coexist
- SUBSIZED requires SIZED
- SORTED requires ORDERED

Stripped ConcurrentMapSpliteratorTester down to just the
CONCURRENT-must-exist assertions and dropped the reflection methods
to match the other ConcurrentMap*Tester classes.

Author: nickita-khylkouski

guava-testlib/src/com/google/common/collect/testing/testers/CollectionSpliteratorTester.java

@@ -75,6 +75,56 @@ public void testSpliteratorNotImmutable_collectionAllowsRemove() {
     assertFalse(collection.spliterator().hasCharacteristics(Spliterator.IMMUTABLE));
   }
 
+  /**
+   * Tests that the spliterator does not report both {@code CONCURRENT} and {@code SIZED}
+   * characteristics, which are incompatible per the {@link Spliterator} specification.
+   */
+  public void testSpliteratorNotConcurrentAndSized() {
+    Spliterator<E> spliterator = collection.spliterator();
+    assertFalse(
+        "spliterator should not have both CONCURRENT and SIZED characteristics",
+        spliterator.hasCharacteristics(Spliterator.CONCURRENT)
+            && spliterator.hasCharacteristics(Spliterator.SIZED));
+  }
+
+  /**
+   * Tests that the spliterator does not report both {@code CONCURRENT} and {@code IMMUTABLE}
+   * characteristics, which are incompatible per the {@link Spliterator} specification.
+   */
+  public void testSpliteratorNotConcurrentAndImmutable() {
+    Spliterator<E> spliterator = collection.spliterator();
+    assertFalse(
+        "spliterator should not have both CONCURRENT and IMMUTABLE characteristics",
+        spliterator.hasCharacteristics(Spliterator.CONCURRENT)
+            && spliterator.hasCharacteristics(Spliterator.IMMUTABLE));
+  }
+
+  /**
+   * Tests that if the spliterator reports {@code SORTED}, it also reports {@code ORDERED}, as
+   * required by the {@link Spliterator} specification.
+   */
+  public void testSpliteratorSortedRequiresOrdered() {
+    Spliterator<E> spliterator = collection.spliterator();
+    if (spliterator.hasCharacteristics(Spliterator.SORTED)) {
+      assertTrue(
+          "spliterator reporting SORTED must also report ORDERED",
+          spliterator.hasCharacteristics(Spliterator.ORDERED));
+    }
+  }
+
+  /**
+   * Tests that if the spliterator reports {@code SUBSIZED}, it also reports {@code SIZED}, as
+   * required by the {@link Spliterator} specification.
+   */
+  public void testSpliteratorSubsizedRequiresSized() {
+    Spliterator<E> spliterator = collection.spliterator();
+    if (spliterator.hasCharacteristics(Spliterator.SUBSIZED)) {
+      assertTrue(
+          "spliterator reporting SUBSIZED must also report SIZED",
+          spliterator.hasCharacteristics(Spliterator.SIZED));
+    }
+  }
+
   @J2ktIncompatible
   @GwtIncompatible // reflection
   public static Method getSpliteratorNotImmutableCollectionAllowsAddMethod() {

guava-testlib/src/com/google/common/collect/testing/testers/ConcurrentMapSpliteratorTester.java

@@ -16,13 +16,8 @@
 
 package com.google.common.collect.testing.testers;
 
-import static com.google.common.collect.testing.Helpers.getMethod;
-
 import com.google.common.annotations.GwtCompatible;
-import com.google.common.annotations.GwtIncompatible;
-import com.google.common.annotations.J2ktIncompatible;
 import com.google.common.collect.testing.AbstractMapTester;
-import java.lang.reflect.Method;
 import java.util.Spliterator;
 import java.util.concurrent.ConcurrentMap;
 import org.jspecify.annotations.NullMarked;
@@ -32,15 +27,14 @@
  * A generic JUnit test which tests spliterator characteristics on concurrent map views. Verifies
  * that {@link ConcurrentMap} implementations return spliterators with the {@link
  * Spliterator#CONCURRENT} characteristic on their {@code entrySet()}, {@code keySet()}, and {@code
- * values()} views, and that no spliterator reports both {@code CONCURRENT} and {@code SIZED}
- * characteristics (which are mutually incompatible per the Java specification).
+ * values()} views.
  *
  * <p>Can't be invoked directly; please see {@link
  * com.google.common.collect.testing.ConcurrentMapTestSuiteBuilder}.
  *
  * @author Guava Authors
  */
-@GwtCompatible(emulated = true)
+@GwtCompatible
 @Ignore("test runners must not instantiate and run this directly, only via suites we build")
 // @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
 @SuppressWarnings("JUnit4ClassUsedInJUnit3")
@@ -83,84 +77,4 @@ public void testValuesSpliteratorHasConcurrent() {
         "values().spliterator() should have CONCURRENT characteristic",
         spliterator.hasCharacteristics(Spliterator.CONCURRENT));
   }
-
-  /**
-   * Tests that the spliterator returned by {@code entrySet().spliterator()} does not have both
-   * {@code CONCURRENT} and {@code SIZED} characteristics, which are mutually incompatible per the
-   * Java specification.
-   */
-  public void testEntrySetSpliteratorNotConcurrentAndSized() {
-    Spliterator<?> spliterator = getMap().entrySet().spliterator();
-    assertFalse(
-        "entrySet().spliterator() should not have both CONCURRENT and SIZED characteristics",
-        spliterator.hasCharacteristics(Spliterator.CONCURRENT)
-            && spliterator.hasCharacteristics(Spliterator.SIZED));
-  }
-
-  /**
-   * Tests that the spliterator returned by {@code keySet().spliterator()} does not have both {@code
-   * CONCURRENT} and {@code SIZED} characteristics, which are mutually incompatible per the Java
-   * specification.
-   */
-  public void testKeySetSpliteratorNotConcurrentAndSized() {
-    Spliterator<?> spliterator = getMap().keySet().spliterator();
-    assertFalse(
-        "keySet().spliterator() should not have both CONCURRENT and SIZED characteristics",
-        spliterator.hasCharacteristics(Spliterator.CONCURRENT)
-            && spliterator.hasCharacteristics(Spliterator.SIZED));
-  }
-
-  /**
-   * Tests that the spliterator returned by {@code values().spliterator()} does not have both {@code
-   * CONCURRENT} and {@code SIZED} characteristics, which are mutually incompatible per the Java
-   * specification.
-   */
-  public void testValuesSpliteratorNotConcurrentAndSized() {
-    Spliterator<?> spliterator = getMap().values().spliterator();
-    assertFalse(
-        "values().spliterator() should not have both CONCURRENT and SIZED characteristics",
-        spliterator.hasCharacteristics(Spliterator.CONCURRENT)
-            && spliterator.hasCharacteristics(Spliterator.SIZED));
-  }
-
-  // Reflection methods for test suppression
-
-  @J2ktIncompatible
-  @GwtIncompatible // reflection
-  public static Method getEntrySetSpliteratorHasConcurrentMethod() {
-    return getMethod(ConcurrentMapSpliteratorTester.class, "testEntrySetSpliteratorHasConcurrent");
-  }
-
-  @J2ktIncompatible
-  @GwtIncompatible // reflection
-  public static Method getKeySetSpliteratorHasConcurrentMethod() {
-    return getMethod(ConcurrentMapSpliteratorTester.class, "testKeySetSpliteratorHasConcurrent");
-  }
-
-  @J2ktIncompatible
-  @GwtIncompatible // reflection
-  public static Method getValuesSpliteratorHasConcurrentMethod() {
-    return getMethod(ConcurrentMapSpliteratorTester.class, "testValuesSpliteratorHasConcurrent");
-  }
-
-  @J2ktIncompatible
-  @GwtIncompatible // reflection
-  public static Method getEntrySetSpliteratorNotConcurrentAndSizedMethod() {
-    return getMethod(
-        ConcurrentMapSpliteratorTester.class, "testEntrySetSpliteratorNotConcurrentAndSized");
-  }
-
-  @J2ktIncompatible
-  @GwtIncompatible // reflection
-  public static Method getKeySetSpliteratorNotConcurrentAndSizedMethod() {
-    return getMethod(
-        ConcurrentMapSpliteratorTester.class, "testKeySetSpliteratorNotConcurrentAndSized");
-  }
-
-  @J2ktIncompatible
-  @GwtIncompatible // reflection
-  public static Method getValuesSpliteratorNotConcurrentAndSizedMethod() {
-    return getMethod(
-        ConcurrentMapSpliteratorTester.class, "testValuesSpliteratorNotConcurrentAndSized");
-  }
 }