diff --git a/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java b/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
index fb3da2df549..60f37808f51 100644
--- a/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
+++ b/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
@@ -1255,18 +1255,27 @@ void testCastStringToDateTime(CastType castType, SqlOperatorFixture f) {
           "1945-02-24 12:42:25.34", "TIMESTAMP(2) NOT NULL");
     }
     if (Bug.CALCITE_5678_FIXED) {
-      f.checkFails("cast('1945-2-2 12:2:5' as TIMESTAMP)",
-              "Invalid DATE value, '1945-2-2 12:2:5'", true);
+      if (castType == CastType.CAST) {
+        f.checkFails("cast('1945-2-2 12:2:5' as TIMESTAMP)",
+            "Invalid DATE value, '1945-2-2 12:2:5'", true);
+        f.checkFails("cast('1241241' as TIMESTAMP)",
+            "Invalid DATE value, '1241241'", true);
+        f.checkFails("cast('1945-20-24 12:42:25.34' as TIMESTAMP)",
+            "Invalid DATE value, '1945-20-24 12:42:25.34'", true);
+        f.checkFails("cast('1945-01-24 25:42:25.34' as TIMESTAMP)",
+            "Value of HOUR field is out of range in '1945-01-24 25:42:25.34'", true);
+        f.checkFails("cast('1945-1-24 12:23:34.454' as TIMESTAMP)",
+            "Invalid DATE value, '1945-1-24 12:23:34.454'", true);
+      } else {
+        // test cases for 'SAFE_CAST' and 'TRY_CAST'
+        f.checkNull("cast('1945-2-2 12:2:5' as TIMESTAMP)");
+        f.checkNull("cast('1241241' as TIMESTAMP)");
+        f.checkNull("cast('1945-20-24 12:42:25.34' as TIMESTAMP)");
+        f.checkNull("cast('1945-01-24 25:42:25.34' as TIMESTAMP)");
+        f.checkNull("cast('1945-1-24 12:23:34.454' as TIMESTAMP)");
+      }
     }
     f.checkFails("cast('nottime' as TIMESTAMP)", BAD_DATETIME_MESSAGE, true);
-    f.checkScalar("cast('1241241' as TIMESTAMP)",
-        "1241-01-01 00:00:00", "TIMESTAMP(0) NOT NULL");
-    f.checkScalar("cast('1945-20-24 12:42:25.34' as TIMESTAMP)",
-        "1946-08-26 12:42:25", "TIMESTAMP(0) NOT NULL");
-    f.checkScalar("cast('1945-01-24 25:42:25.34' as TIMESTAMP)",
-        "1945-01-25 01:42:25", "TIMESTAMP(0) NOT NULL");
-    f.checkScalar("cast('1945-1-24 12:23:34.454' as TIMESTAMP)",
-        "1945-01-24 12:23:34", "TIMESTAMP(0) NOT NULL");
 
     // date <-> string
     f.checkCastToString("DATE '1945-02-24'", null, "1945-02-24", castType);