New lexer for mojom written in go.

mojom/mojom_parser/lexer/lexer_test.go

Index: mojom/mojom_parser/lexer/lexer_test.go
diff --git a/mojom/mojom_parser/lexer/lexer_test.go b/mojom/mojom_parser/lexer/lexer_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..52ad247bd6bf6dab92ddd8f4a1a87acfae1faea0
--- /dev/null
+++ b/mojom/mojom_parser/lexer/lexer_test.go
@@ -0,0 +1,190 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package lexer
+
+import "testing"
+
+func checkEq(t *testing.T, expected, actual interface{}) {
+	if expected != actual {
+		t.Fatalf("Failed check: Expected (%v), Actual (%v)", expected, actual)
+	}
+}
+

[rudominer, 2015/10/12 18:06:06]

Can you add a test where
- the input string is empty
- the input string contains bytes that are not valid UTF8 

[azani, 2015/10/13 00:23:46]

Done.

+// pumpTokens pumps all the tokens from a channel into a slice.
+func pumpTokens(tokensChan chan Token) []Token {
+	tokens := []Token{}
+	for token := range tokensChan {
+		tokens = append(tokens, token)
+	}
+	return tokens
+}
+
+// TestAllSingleTokens tests for each token that a valid string is accepted as
+// the correct token.
+func TestAllSingleTokens(t *testing.T) {
+	testData := []struct {
+		source string
+		token  TokenKind
+	}{
+		{"(", LPAREN},
+		{")", RPAREN},
+		{"[", LBRACKET},
+		{"]", RBRACKET},
+		{"{", LBRACE},
+		{"}", RBRACE},
+		{"<", LANGLE},
+		{">", RANGLE},
+		{";", SEMI},
+		{",", COMMA},
+		{".", DOT},
+		{"-", MINUS},
+		{"+", PLUS},
+		{"&", AMP},
+		{"?", QSTN},
+		{"=", EQUALS},
+		{"=>", RESPONSE},
+		{"somet_hi3ng", NAME},
+		{"import", IMPORT},
+		{"module", MODULE},
+		{"struct", STRUCT},
+		{"union", UNION},
+		{"interface", INTERFACE},
+		{"enum", ENUM},
+		{"const", CONST},
+		{"true", TRUE},
+		{"false", FALSE},
+		{"default", DEFAULT},
+		{"@10", ORDINAL},
+		{"10", INT_CONST_DEC},
+		{"0", INT_CONST_DEC},
+		{"0xA10", INT_CONST_HEX},
+		{"0xa10", INT_CONST_HEX},
+		{"0XA10", INT_CONST_HEX},
+		{"0Xa10", INT_CONST_HEX},
+		{"10.5", FLOAT_CONST},
+		{"10e5", FLOAT_CONST},
+		{"0.5", FLOAT_CONST},
+		{"0e5", FLOAT_CONST},
+		{"10e+5", FLOAT_CONST},
+		{"10e-5", FLOAT_CONST},
+		{"\"hello world\"", STRING_LITERAL},
+		{"\"hello \\\"real\\\" world\"", STRING_LITERAL},
+	}
+
+	for i := range testData {
+		l := lexer{source: testData[i].source, tokens: make(chan Token)}
+		go l.run()
+		tokens := pumpTokens(l.tokens)
+
+		if len(tokens) != 1 {
+			t.Fatalf("Source('%v'): Expected 1 token but got %v instead: %v",
+				testData[i].source, len(tokens), tokens)
+		}
+
+		checkEq(t, testData[i].source, tokens[0].Text)
+		checkEq(t, testData[i].token, tokens[0].Kind)
+	}
+}
+
+// TestTokenPosition tests that the position in the source string, the line
+// number and the position in the line of the lexed token are correctly found.
+func TestTokenPosition(t *testing.T) {
+	source := "  \n  ."
+	l := lexer{source: source, tokens: make(chan Token)}
+	go l.run()
+	tokens := pumpTokens(l.tokens)
+	token := tokens[0]
+
+	checkEq(t, 5, token.CharPos)
+	checkEq(t, 1, token.LineNo)
+	checkEq(t, 2, token.LinePos)
+}
+
+// TestSkipSkippable tests that all skippable characters are skipped.
+func TestSkipSkippable(t *testing.T) {
+	source := "  \t  \r \n  ."
+	l := lexer{source: source, tokens: make(chan Token)}
+	go l.run()
+	tokens := pumpTokens(l.tokens)
+
+	checkEq(t, DOT, tokens[0].Kind)
+}
+
+// TestTokenize tests that a single token embedded in a larger string is
+// correctly lexed.
+func TestTokenize(t *testing.T) {
+	ts := Tokenize("   \t .   ")
+	token := ts.PeekNext()
+	checkEq(t, DOT, token.Kind)
+
+	ts.ConsumeNext()
+	token = ts.PeekNext()
+	checkEq(t, EOF, token.Kind)
+}
+
+// TestTokenizeMoreThanOne tests that more than one token is correctly lexed.
+func TestTokenizeMoreThanOne(t *testing.T) {
+	ts := Tokenize("()")
+	checkEq(t, LPAREN, ts.PeekNext().Kind)
+	ts.ConsumeNext()
+	checkEq(t, RPAREN, ts.PeekNext().Kind)
+	ts.ConsumeNext()
+	checkEq(t, EOF, ts.PeekNext().Kind)
+}
+
+// TestIllegalChar tests that an illegal character is correctly spotted.
+func TestIllegalChar(t *testing.T) {
+	ts := Tokenize("   \t $   ")
+	checkEq(t, ERROR_ILLEGAL_CHAR, ts.PeekNext().Kind)
+}
+
+// TestUnterminatedStringLiteralEos tests that the correct error is emitted if
+// a quoted string is never closed.
+func TestUnterminatedStringLiteralEos(t *testing.T) {
+	ts := Tokenize("\"hello world")
+	checkEq(t, ERROR_UNTERMINATED_STRING_LITERAL, ts.PeekNext().Kind)
+}
+
+// TestUnterminatedStringLiteralEol tests that the correct error is emitted if
+// a quoted string is closed on a subsequent line.
+func TestUnterminatedStringLiteralEol(t *testing.T) {
+	ts := Tokenize("\"hello\n world\"")
+	checkEq(t, ERROR_UNTERMINATED_STRING_LITERAL, ts.PeekNext().Kind)
+}
+
+// TestSingleLineComment tests that single line comments are correctly skipped.
+func TestSingleLineComment(t *testing.T) {
+	ts := Tokenize("( // some stuff\n)")
+	checkEq(t, LPAREN, ts.PeekNext().Kind)
+	ts.ConsumeNext()
+	checkEq(t, RPAREN, ts.PeekNext().Kind)
+}
+
+// TestMultiLineComment tests that multi line comments are correctly skipped.
+func TestMultiLineComment(t *testing.T) {
+	ts := Tokenize("( /* hello world/  * *\n */)")
+	checkEq(t, LPAREN, ts.PeekNext().Kind)
+	ts.ConsumeNext()
+	checkEq(t, RPAREN, ts.PeekNext().Kind)
+}
+
+// TestUnterminatedMultiLineComment tests that unterminated multiline comments
+// emit the correct error.
+func TestUnterminatedMultiLineComment(t *testing.T) {
+	ts := Tokenize("( /* hello world/  * *\n )")
+	checkEq(t, LPAREN, ts.PeekNext().Kind)
+	ts.ConsumeNext()
+	checkEq(t, ERROR_UNTERMINATED_COMMENT, ts.PeekNext().Kind)
+}
+
+// TestUnterminatedMultiLineCommentAtStar tests that if the string ends at a *
+// (which could be the beginning of the close of a multiline comment) the right
+// error is emitted.
+func TestUnterminatedMultiLineCommentAtStar(t *testing.T) {
+	ts := Tokenize("( /* hello world/  *")
+	checkEq(t, LPAREN, ts.PeekNext().Kind)
+	ts.ConsumeNext()
+	checkEq(t, ERROR_UNTERMINATED_COMMENT, ts.PeekNext().Kind)
+}