### Question:
GOLDParser extends Parser { public List<String> validateHandlersExist() throws ParserException { List<String> errors = new ArrayList<String>(); for (Production production : productionTable) { String rule = production.toString(); if (ruleHandlers.get(rule) == null && ruleHandlers.get(rule.replace("'", "")) == null) { errors.add(FormatHelper.formatMessage("messages", "error.handler_none", rule)); } } return errors; } GOLDParser();  GOLDParser(GOLDParserBuildContext context);  GOLDParser(File cgtFile, String rulesPackage, boolean trimReductions);  GOLDParser(InputStream cgtFile, String rulesPackage, boolean trimReductions); void clear(); void clearProgramVariables(); void clearProgramVariable(String name); Variable getProgramVariable(String name); void setProgramVariable(String name, Variable value); Map<String, Scope> getScopes(); Scope getCurrentScope(); Scope setCurrentScope(Scope newScope); boolean getGenerateTree(); void setGenerateTree(boolean generateTree); void raiseParserException(String msg); void raiseParserException(String msg, Throwable cause); List<String> getErrorMessages(); String getErrorMessage(); void addErrorMessage(String message); boolean isReady(); boolean isIgnoreCaseOfVariables(); void setIgnoreCaseOfVariables(boolean ignoreCaseOfVariableNames); boolean setup(File grammarFile); boolean parseSourceStatements(String sourceStatements); boolean parseSourceStatements(Reader sourceReader); boolean processInternalError(); String getParseTree(); void loadRuleHandlers(String packageName); void loadRuleHandlers(List<Class> ruleClasses); List<String> validateHandlersExist(); void validateHandlerExists(Production rule); static final String VT_INDENT_DECREASE; static final String VT_INDENT_INCREASE; }### Answer:
@Test public void testValidHandlersExist() throws Exception { GOLDParserForTesting parser = new GOLDParserForTesting(new File("src/test/resources/parser/Simple2.cgt"), "com.creativewidgetworks.goldparser.simple2", true); assertEquals("expected empty list", 0, parser.validateHandlersExist().size()); parser = new GOLDParserForTesting(new File("src/test/resources/parser/Simple2.cgt"), "com.creativewidgetworks.goldparser.simple3", true); String[] expected = { "No rule handler for rule <Statements> ::= <Statement> <Statements>", "No rule handler for rule <Statements> ::= <Statement>", "No rule handler for rule <Statement> ::= display <Expression>", "No rule handler for rule <Statement> ::= display <Expression> read Id", "No rule handler for rule <Statement> ::= assign Id '=' <Expression>"}; List<String> errors = parser.validateHandlersExist(); assertEquals("expected errors", expected.length, errors.size()); for (int i = 0; i < expected.length; i++) { assertEquals("wrong message at index " + i, expected[i], errors.get(i)); } }