Add tests for handling quoted scalars

ballerina/tests/parse_string.bal

@@ -751,7 +751,7 @@ isolated function testParsingEmptyLines() returns error? {
     map<string> value = check parseString(content);
     map<string> expectedResult = {
         "FoldingDoubleQuote": "Empty line\nas a line feed",
-        "FoldingSingleQuote": "Empty line\nas a line feed",
+        "FoldingSingleQuote": "Empty line\n'as a line 'feed",
         "Chomping": "Clipped empty lines\n"
     };
     test:assertEquals(value, expectedResult);

ballerina/tests/parse_string_negative.bal

@@ -46,7 +46,29 @@ function negativeDataProvider() returns [string, string][] => [
     ["negative_test_11.yaml", "'unexpected event' at line: '1' column: '8'"],
     ["negative_test_12.yaml", "'unexpected event error' at line: '1' column: '5'"],
     ["negative_test_13.yaml", "'cannot have block sequence under flow collection' at line: '2' column: '3'"],
-    ["negative_test_14.yaml", "''-' cannot be defined after tag properties' at line: '1' column: '7'"]
+    ["negative_test_14.yaml", "''-' cannot be defined after tag properties' at line: '1' column: '7'"],
+    [
+        "negative_test_15.yaml",
+        "'invalid token 'DOCUMENT_MARKER' inside the double-quoted scalar'" +
+        " at line: '3' column: '3'"
+    ],
+    [
+        "negative_test_16.yaml",
+        "'invalid token 'DIRECTIVE_MARKER' inside the double-quoted scalar'" +
+        " at line: '3' column: '3'"
+    ],
+    [
+        "negative_test_17.yaml",
+        "'invalid token 'DOCUMENT_MARKER' inside the single-quoted scalar'" +
+        " at line: '3' column: '3'"
+    ],
+    [
+        "negative_test_18.yaml",
+        "'invalid token 'DIRECTIVE_MARKER' inside the single-quoted scalar'" +
+        " at line: '3' column: '3'"
+    ],
+    ["negative_test_19.yaml", "'invalid block header' at line: '1' column: '10'"]
+
 ];
 
 @test:Config {

ballerina/tests/resources/negative/negative_test_15.yaml

@@ -0,0 +1,4 @@
+invalid-block-scalar:
+  "invalid double quoted
+...
+  bloack scalar"

ballerina/tests/resources/negative/negative_test_16.yaml

@@ -0,0 +1,4 @@
+invalid-block-scalar:
+  "invalid double quoted
+---
+  bloack scalar"

ballerina/tests/resources/negative/negative_test_17.yaml

@@ -0,0 +1,4 @@
+invalid-block-scalar:
+  'invalid singlw quoted
+...
+  bloack scalar'

ballerina/tests/resources/negative/negative_test_18.yaml

@@ -0,0 +1,4 @@
+invalid-block-scalar:
+  'invalid single quoted
+---
+  bloack scalar'

ballerina/tests/resources/negative/negative_test_19.yaml

@@ -0,0 +1,3 @@
+invalid: |*
+
+ foo

ballerina/tests/resources/nested_20.yaml

@@ -5,6 +5,6 @@ FoldingDoubleQuote:
 FoldingSingleQuote:
   'Empty line
   
-  as a line feed'
+  ''as a line ''feed'
 Chomping: |
   Clipped empty lines

native/src/main/java/io/ballerina/lib/data/yaml/lexer/LexerState.java

@@ -754,9 +754,7 @@ public State transition(LexerState lexerState) throws Error.YamlParserException
             // Check for empty lines
             if (WHITE_SPACE_PATTERN.pattern(lexerState.peek())) {
                 String whitespace = getWhitespace(lexerState);
-                if (lexerState.peek() == -1) {
-                    lexerState.forward();
-                    lexerState.tokenize(EMPTY_LINE);
+                if (Scanner.scanAndTokenizeEOL(lexerState, EMPTY_LINE)) {
                     return this;
                 }
                 if (lexerState.firstLine) {
@@ -803,9 +801,7 @@ public State transition(LexerState lexerState) throws Error.YamlParserException
             // Check for empty lines
             if (WHITE_SPACE_PATTERN.pattern(lexerState.peek())) {
                 String whitespace = getWhitespace(lexerState);
-                if (lexerState.peek() == -1) {
-                    lexerState.forward();
-                    lexerState.tokenize(EMPTY_LINE);
+                if (Scanner.scanAndTokenizeEOL(lexerState, EMPTY_LINE)) {
                     return this;
                 }
                 if (lexerState.firstLine) {

native/src/main/java/io/ballerina/lib/data/yaml/parser/YamlParser.java

@@ -2183,8 +2183,11 @@ private static String doubleQuoteScalar(ParserState state) throws Error.YamlPars
                     }
                     state.getLexerState().setFirstLine(false);
                 }
-                default -> throw new Error.YamlParserException("invalid double quote scalar",
-                        state.getLine(), state.getColumn());
+                default -> {
+                    String errorMsg = "invalid token '" + state.getCurrentToken().getType()
+                            + "' inside the double-quoted scalar";
+                    throw new Error.YamlParserException(errorMsg, state.getLine(), state.getColumn());
+                }
             }
             getNextToken(state);
         }
@@ -2220,7 +2223,8 @@ private static void checkEmptyKey(ParserState state) throws Error.YamlParserExce
         }
     }
 
-    /** Parse the string of a single-quoted scalar.
+    /**
+     * Parse the string of a single-quoted scalar.
      *
      * @param state - Current parser state
      * @return - Parsed single-quoted scalar value
@@ -2279,8 +2283,11 @@ private static String singleQuoteScalar(ParserState state) throws Error.YamlPars
                     }
                     state.getLexerState().setFirstLine(false);
                 }
-                default -> throw new Error.YamlParserException("invalid single quote character",
-                        state.getLine(), state.getColumn());
+                default -> {
+                    String errorMsg = "invalid token '" + state.getCurrentToken().getType()
+                            + "' inside the single-quoted scalar";
+                    throw new Error.YamlParserException(errorMsg, state.getLine(), state.getColumn());
+                }
             }
             getNextToken(state);
         }