First commit

vendor/github.com/tdewolff/parse/buffer/lexer_test.go

@@ -0,0 +1,91 @@
+package buffer // import "github.com/tdewolff/parse/buffer"
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	"github.com/tdewolff/test"
+)
+
+func TestLexer(t *testing.T) {
+	s := `Lorem ipsum dolor sit amet, consectetur adipiscing elit.`
+	z := NewLexer(bytes.NewBufferString(s))
+
+	test.T(t, z.err, nil, "buffer has no error")
+	test.T(t, z.Err(), nil, "buffer is at EOF but must not return EOF until we reach that")
+	test.That(t, z.Pos() == 0, "buffer must start at position 0")
+	test.That(t, z.Peek(0) == 'L', "first character must be 'L'")
+	test.That(t, z.Peek(1) == 'o', "second character must be 'o'")
+
+	z.Move(1)
+	test.That(t, z.Peek(0) == 'o', "must be 'o' at position 1")
+	test.That(t, z.Peek(1) == 'r', "must be 'r' at position 1")
+	z.Rewind(6)
+	test.That(t, z.Peek(0) == 'i', "must be 'i' at position 6")
+	test.That(t, z.Peek(1) == 'p', "must be 'p' at position 7")
+
+	test.Bytes(t, z.Lexeme(), []byte("Lorem "), "buffered string must now read 'Lorem ' when at position 6")
+	test.Bytes(t, z.Shift(), []byte("Lorem "), "shift must return the buffered string")
+	test.That(t, z.Pos() == 0, "after shifting position must be 0")
+	test.That(t, z.Peek(0) == 'i', "must be 'i' at position 0 after shifting")
+	test.That(t, z.Peek(1) == 'p', "must be 'p' at position 1 after shifting")
+	test.T(t, z.Err(), nil, "error must be nil at this point")
+
+	z.Move(len(s) - len("Lorem ") - 1)
+	test.T(t, z.Err(), nil, "error must be nil just before the end of the buffer")
+	z.Skip()
+	test.That(t, z.Pos() == 0, "after skipping position must be 0")
+	z.Move(1)
+	test.T(t, z.Err(), io.EOF, "error must be EOF when past the buffer")
+	z.Move(-1)
+	test.T(t, z.Err(), nil, "error must be nil just before the end of the buffer, even when it has been past the buffer")
+}
+
+func TestLexerRunes(t *testing.T) {
+	z := NewLexer(bytes.NewBufferString("aæ†\U00100000"))
+	r, n := z.PeekRune(0)
+	test.That(t, n == 1, "first character must be length 1")
+	test.That(t, r == 'a', "first character must be rune 'a'")
+	r, n = z.PeekRune(1)
+	test.That(t, n == 2, "second character must be length 2")
+	test.That(t, r == 'æ', "second character must be rune 'æ'")
+	r, n = z.PeekRune(3)
+	test.That(t, n == 3, "fourth character must be length 3")
+	test.That(t, r == '†', "fourth character must be rune '†'")
+	r, n = z.PeekRune(6)
+	test.That(t, n == 4, "seventh character must be length 4")
+	test.That(t, r == '\U00100000', "seventh character must be rune '\U00100000'")
+}
+
+func TestLexerBadRune(t *testing.T) {
+	z := NewLexer(bytes.NewBufferString("\xF0")) // expect four byte rune
+	r, n := z.PeekRune(0)
+	test.T(t, n, 1, "length")
+	test.T(t, r, rune(0xF0), "rune")
+}
+
+func TestLexerZeroLen(t *testing.T) {
+	z := NewLexer(test.NewPlainReader(bytes.NewBufferString("")))
+	test.That(t, z.Peek(0) == 0, "first character must yield error")
+}
+
+func TestLexerEmptyReader(t *testing.T) {
+	z := NewLexer(test.NewEmptyReader())
+	test.That(t, z.Peek(0) == 0, "first character must yield error")
+	test.T(t, z.Err(), io.EOF, "error must be EOF")
+	test.That(t, z.Peek(0) == 0, "second peek must also yield error")
+}
+
+func TestLexerErrorReader(t *testing.T) {
+	z := NewLexer(test.NewErrorReader(0))
+	test.That(t, z.Peek(0) == 0, "first character must yield error")
+	test.T(t, z.Err(), test.ErrPlain, "error must be ErrPlain")
+	test.That(t, z.Peek(0) == 0, "second peek must also yield error")
+}
+
+func TestLexerBytes(t *testing.T) {
+	b := []byte{'t', 'e', 's', 't'}
+	z := NewLexerBytes(b)
+	test.That(t, z.Peek(4) == 0, "fifth character must yield NULL")
+}