diff --git a/core/src/test/java/org/apache/calcite/test/RelMetadataTest.java b/core/src/test/java/org/apache/calcite/test/RelMetadataTest.java
index b3f1c34beb0d..d9733486bd6a 100644
--- a/core/src/test/java/org/apache/calcite/test/RelMetadataTest.java
+++ b/core/src/test/java/org/apache/calcite/test/RelMetadataTest.java
@@ -1951,21 +1951,41 @@ public String colType(MyRelMetadataQuery myRelMetadataQuery, RelNode rel, int co
   /**
    * Test case for
    * <a href="https://issues.apache.org/jira/browse/CALCITE-6338">[CALCITE-6338]
-   * RelMdCollation#project can return an incomplete list of collations</a>.
+   * RelMdCollation#project can return an incomplete list of collations
+   * in the presence of aliasing</a>.
    */
-  @Test void testCollationProject() {
+  @Test void testCollationProjectAliasing() {
     final RelBuilder builder = RelBuilderTest.createBuilder();
-    final RelNode relNode = builder
+    final RelNode relNode1 = builder
         .scan("EMP")
         .sort(2, 3)
         .project(builder.field(0), builder.field(2), builder.field(2), builder.field(3))
         .build();
+    checkCollationProjectAliasing(relNode1, "[[1, 3], [2, 3]]");
+    final RelNode relNode2 = builder
+        .scan("EMP")
+        .sort(0, 1)
+        .project(builder.field(0), builder.field(0), builder.field(1), builder.field(1))
+        .build();
+    checkCollationProjectAliasing(relNode2, "[[0, 2], [0, 3], [1, 2], [1, 3]]");
+    final RelNode relNode3 = builder
+        .scan("EMP")
+        .sort(0, 1, 2)
+        .project(
+            builder.field(0), builder.field(0),
+            builder.field(1), builder.field(1), builder.field(1),
+            builder.field(2))
+        .build();
+    checkCollationProjectAliasing(relNode3,
+        "[[0, 2, 5], [0, 3, 5], [0, 4, 5], [1, 2, 5], [1, 3, 5], [1, 4, 5]]");
+  }
 
-    assertThat(relNode, instanceOf(Project.class));
+  private void checkCollationProjectAliasing(RelNode relNode, String expectedCollation) {
     final RelMetadataQuery mq = relNode.getCluster().getMetadataQuery();
+    assertThat(relNode, instanceOf(Project.class));
     final ImmutableList<RelCollation> collations = mq.collations(relNode);
     assertThat(collations, notNullValue());
-    assertEquals("[[1, 3], [2, 3]]", collations.toString());
+    assertEquals(expectedCollation, collations.toString());
   }
 
   /** Unit test for