Test casts of date to bounded varchar

core/trino-main/src/test/java/io/trino/sql/TestExpressionInterpreter.java

@@ -833,6 +833,17 @@ public void testCastRealToBoundedVarchar()
                 .hasMessage("Value 1200000.0 cannot be represented as varchar(5)");
     }
 
+    @Test
+    public void testCastDateToBoundedVarchar()
+    {
+        assertEvaluatedEquals("CAST(DATE '2013-02-02' AS varchar(10))", "'2013-02-02'");
+        assertEvaluatedEquals("CAST(DATE '-2013-02-02' AS varchar(50))", "'-2013-02-02'");
+
+        // incorrect behavior: the result value does not fit in the type
+        assertEvaluatedEquals("CAST(DATE '2013-02-02' AS varchar(9))", "'2013-02-02'");
+        assertEvaluatedEquals("CAST(DATE '-2013-02-02' AS varchar(9))", "'-2013-02-02'");
+    }
+
     @Test
     public void testCastToBoolean()
     {

core/trino-main/src/test/java/io/trino/sql/planner/iterative/rule/TestSimplifyExpressions.java

@@ -44,6 +44,7 @@
 import static io.trino.sql.planner.TypeAnalyzer.createTestingTypeAnalyzer;
 import static io.trino.sql.planner.iterative.rule.SimplifyExpressions.rewrite;
 import static java.util.stream.Collectors.toList;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.testng.Assert.assertEquals;
 
 public class TestSimplifyExpressions
@@ -242,6 +243,23 @@ public void testCastRealToBoundedVarchar()
         assertSimplifies("CAST(REAL '12e2' AS varchar(3)) = '1200.0'", "CAST(REAL '12e2' AS varchar(3)) = '1200.0'");
     }
 
+    @Test
+    public void testCastDateToBoundedVarchar()
+    {
+        // the varchar type length is enough to contain the date's representation
+        assertSimplifies("CAST(DATE '2013-02-02' AS varchar(10))", "'2013-02-02'");
+        assertSimplifies("CAST(DATE '2013-02-02' AS varchar(50))", "CAST('2013-02-02' AS varchar(50))");
+
+        // the cast operator returns a value that is too long for the expected type ('2013-02-02' for varchar(3))
+        // the LiteralEncoder detects the mismatch and fails
+        assertThatThrownBy(() -> simplify("CAST(DATE '2013-02-02' AS varchar(3))"))
+                .hasMessage("Value [2013-02-02] does not fit in type varchar(3)");
+
+        // the cast operator returns a value that is too long for the expected type ('2013-02-02' for varchar(3))
+        // the value is nested in a comparison expression, so the mismatch is not detected by the LiteralEncoder
+        assertSimplifies("CAST(DATE '2013-02-02' AS varchar(3)) = '2013-02-02'", "true");
+    }
+
     private static void assertSimplifies(String expression, String expected)
     {
         Expression expectedExpression = normalize(rewriteIdentifiersToSymbolReferences(SQL_PARSER.createExpression(expected, new ParsingOptions())));

core/trino-main/src/test/java/io/trino/type/TestDateTimeOperators.java

@@ -32,6 +32,7 @@
 import static io.trino.spi.type.TimestampType.createTimestampType;
 import static io.trino.spi.type.TimestampWithTimeZoneType.TIMESTAMP_TZ_MILLIS;
 import static io.trino.spi.type.VarcharType.VARCHAR;
+import static io.trino.spi.type.VarcharType.createVarcharType;
 import static io.trino.testing.DateTimeTestingUtils.sqlTimestampOf;
 import static io.trino.testing.TestingSession.testSessionBuilder;
 import static org.joda.time.DateTimeZone.UTC;
@@ -264,6 +265,18 @@ public void testDateCastFromVarchar()
         assertInvalidFunction("DATE '392251590-07-12'", INVALID_CAST_ARGUMENT, "Value cannot be cast to date: 392251590-07-12");
     }
 
+    @Test
+    public void testDateCastToVarchar()
+    {
+        assertFunction("cast(DATE '2013-02-02' AS varchar)", VARCHAR, "2013-02-02");
+        assertFunction("cast(DATE '13-2-2' AS varchar)", VARCHAR, "0013-02-02");
+        assertFunction("cast(DATE '2013-02-02' AS varchar(50))", createVarcharType(50), "2013-02-02");
+        assertFunction("cast(DATE '2013-02-02' AS varchar(10))", createVarcharType(10), "2013-02-02");
+
+        // cast operator returns a value that does not fit in the result type. this causes error in the LiteralEncoder
+        assertFunctionThrowsIncorrectly("cast(DATE '2013-02-02' AS varchar(9))", IllegalArgumentException.class, "Value .2013-02-02. does not fit in type varchar.9.");
+    }
+
     private static SqlDate toDate(DateTime dateTime)
     {
         return new SqlDate((int) TimeUnit.MILLISECONDS.toDays(dateTime.getMillis()));