Added unit tests for errorListener.isErrorFound

Signed-off-by: Steven Bayer <[email protected]>

data-prepper-expression/src/main/java/org/opensearch/dataprepper/expression/CompositeException.java

@@ -22,7 +22,7 @@ public class CompositeException extends RuntimeException {
 
     public CompositeException(final List<Throwable> exceptions) {
         if (exceptions.isEmpty()) {
-            throw new IllegalArgumentException("errors is empty");
+            throw new IllegalArgumentException("exceptions is empty");
         }
 
         this.exceptions = exceptions.stream()

data-prepper-expression/src/main/java/org/opensearch/dataprepper/expression/ParseTreeParser.java

@@ -47,13 +47,16 @@ public ParseTreeParser(final DataPrepperExpressionParser parser, final ParserErr
     /**
      * @since 1.3
      *
-     * Converts an expression to a parse tree base on grammar rules
+     * Converts an expression to a parse tree base on grammar rules. {@link ParserErrorListener#resetErrors()} must be called
+     * before {@link DataPrepperExpressionParser#expression()} to prevent duplicate errors from being reported.
      *
      * @param expression String to be parsed
      * @return ParseTree data structure containing a hierarchy of the tokens found while parsing.
      * @throws CompositeException thrown when ANTLR parser creates an exception event
      */
     private ParseTree createParseTree(final String expression) throws CompositeException {
+        errorListener.resetErrors();
+
         final IntStream input = CharStreams.fromString(expression);
         lexer.setInputStream(input);
 

data-prepper-expression/src/test/java/org/opensearch/dataprepper/expression/CompositeExceptionTest.java

@@ -37,19 +37,21 @@ void testGivenSingleExceptionThenExceptionIsCause() {
     }
 
     @Test
-    void foo() throws CompositeException {
+    void testMultipleExceptionsPrinted() throws CompositeException {
         final CompositeException compositeException = new CompositeException(Arrays.asList(
                 new RuntimeException("Error"),
                 new RuntimeException("Error 2"),
-                new RuntimeException("Error 3")
+                new RuntimeException("Error 3"),
+                null
         ));
 
         assertThat(compositeException.getCause() instanceof ExceptionOverview, is(true));
 
         final String message = compositeException.getCause().getMessage();
-        assertThat(message, containsString("Multiple exceptions (3)"));
+        assertThat(message, containsString("Multiple exceptions (4)"));
         assertThat(message, containsString("|-- java.lang.RuntimeException: Error 3"));
         assertThat(message, containsString("|-- java.lang.RuntimeException: Error 2"));
         assertThat(message, containsString("|-- java.lang.RuntimeException: Error"));
+        assertThat(message, containsString("|-- java.lang.NullPointerException: Throwable was null!"));
     }
 }

data-prepper-expression/src/test/java/org/opensearch/dataprepper/expression/ParseTreeParserTest.java

@@ -23,6 +23,7 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 @ExtendWith(MockitoExtension.class)
@@ -81,6 +82,8 @@ void testCacheGivenMultipleExpressionCalls() throws CompositeException {
         parseTree = parseTreeParser.parse(VALID_STATEMENT);
         assertThat(parseTree, is(expected));
 
+        verify(errorListener).isErrorFound();
+
         // Verify parser.expression() called 1 time
         verify(parser).expression();
     }
@@ -94,4 +97,18 @@ void testExceptionThrowWhenParsingErrorPresent() {
         assertThrows(CompositeException.class, () -> parseTreeParser.parse("Error should throw"));
     }
 
+    @Test
+    void testResetErrorsIsCalled() throws CompositeException {
+        final ParseTree expected = mock(DataPrepperExpressionParser.ExpressionContext.class);
+        doReturn(expected).when(parser).expression();
+
+        ParseTree parseTree = parseTreeParser.parse(VALID_STATEMENT);
+        assertThat(parseTree, is(expected));
+        verify(errorListener).isErrorFound();
+
+        parseTree = parseTreeParser.parse("true == true");
+        assertThat(parseTree, is(expected));
+        verify(errorListener, times(2)).isErrorFound();
+    }
+
 }