Ensure a newline exists at the end of files.

Fixes #42.

_tools/exercise/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"io/ioutil"
+	"os"
 
 	"github.com/alecthomas/chroma/formatters"
 	"github.com/alecthomas/chroma/lexers"
@@ -24,12 +25,14 @@ func main() {
 			fmt.Printf("warning: could not find lexer for %q\n", file)
 			continue
 		}
+		fmt.Printf("%s: ", file)
+		os.Stdout.Sync()
 		text, err := ioutil.ReadFile(file)
 		kingpin.FatalIfError(err, "")
 		it, err := lexer.Tokenise(nil, string(text))
 		kingpin.FatalIfError(err, "%s failed to tokenise %q", lexer.Config().Name, file)
 		err = formatters.NoOp.Format(ioutil.Discard, styles.SwapOff, it)
 		kingpin.FatalIfError(err, "%s failed to format %q", lexer.Config().Name, file)
-		fmt.Printf("ok: %q\n", file)
+		fmt.Printf("ok\n")
 	}
 }

coalesce_test.go

@@ -3,17 +3,17 @@ package chroma
 import (
 	"testing"
 
-	"github.com/stretchr/testify/require"
+	"github.com/alecthomas/assert"
 )
 
 func TestCoalesce(t *testing.T) {
-	lexer := Coalesce(MustNewLexer(nil, Rules{
+	lexer := Coalesce(MustNewLexer(&Config{DontEnsureNL: true}, Rules{
 		"root": []Rule{
 			{`[!@#$%^&*()]`, Punctuation, nil},
 		},
 	}))
 	actual, err := Tokenise(lexer, nil, "!@#$")
-	require.NoError(t, err)
+	assert.NoError(t, err)
 	expected := []*Token{{Punctuation, "!@#$"}}
-	require.Equal(t, expected, actual)
+	assert.Equal(t, expected, actual)
 }

colour_test.go

@@ -3,7 +3,7 @@ package chroma
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/alecthomas/assert"
 )
 
 func TestColourRGB(t *testing.T) {

formatters/html/html_test.go

@@ -5,7 +5,7 @@ import (
 	"io/ioutil"
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/alecthomas/assert"
 
 	"github.com/alecthomas/chroma"
 	"github.com/alecthomas/chroma/lexers"

lexer.go

@@ -46,7 +46,7 @@ type Config struct {
 
 	// Make sure that the input does not end with a newline. This
 	// is required for some lexers that consume input linewise.
-	// DontEnsureNL bool
+	DontEnsureNL bool
 
 	// If given and greater than 0, expand tabs in the input.
 	// TabSize int

lexer_test.go

@@ -3,13 +3,13 @@ package chroma
 import (
 	"testing"
 
-	"github.com/stretchr/testify/require"
+	"github.com/alecthomas/assert"
 )
 
 func TestTokenTypeClassifiers(t *testing.T) {
-	require.True(t, GenericDeleted.InCategory(Generic))
-	require.True(t, LiteralStringBacktick.InSubCategory(String))
-	require.Equal(t, LiteralStringBacktick.String(), "LiteralStringBacktick")
+	assert.True(t, GenericDeleted.InCategory(Generic))
+	assert.True(t, LiteralStringBacktick.InSubCategory(String))
+	assert.Equal(t, LiteralStringBacktick.String(), "LiteralStringBacktick")
 }
 
 func TestSimpleLexer(t *testing.T) {
@@ -28,13 +28,13 @@ func TestSimpleLexer(t *testing.T) {
 			},
 		},
 	)
-	require.NoError(t, err)
+	assert.NoError(t, err)
 	actual, err := Tokenise(lexer, nil, `
 	; this is a comment
 	[section]
 	a = 10
 `)
-	require.NoError(t, err)
+	assert.NoError(t, err)
 	expected := []*Token{
 		{Whitespace, "\n\t"},
 		{Comment, "; this is a comment"},
@@ -48,5 +48,5 @@ func TestSimpleLexer(t *testing.T) {
 		{LiteralString, "10"},
 		{Whitespace, "\n"},
 	}
-	require.Equal(t, expected, actual)
+	assert.Equal(t, expected, actual)
 }

lexers/api_test.go

@@ -4,7 +4,7 @@ import (
 	"io/ioutil"
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/alecthomas/assert"
 
 	"github.com/alecthomas/chroma/formatters"
 	"github.com/alecthomas/chroma/lexers"

lexers/lexer_benchmark_test.go

@@ -3,7 +3,7 @@ package lexers
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/alecthomas/assert"
 )
 
 const lexerBenchSource = `package chroma

lexers/vhdl.go

@@ -33,7 +33,9 @@ var VHDL = Register(MustNewLexer(
 			{`(entity|component)(\s+)([a-z_]\w*)`, ByGroups(Keyword, Text, NameClass), nil},
 			{`(architecture|configuration)(\s+)([a-z_]\w*)(\s+)(of)(\s+)([a-z_]\w*)(\s+)(is)`, ByGroups(Keyword, Text, NameClass, Text, Keyword, Text, NameClass, Text, Keyword), nil},
 			{`([a-z_]\w*)(:)(\s+)(process|for)`, ByGroups(NameClass, Operator, Text, Keyword), nil},
-			{`(end)(\s+)`, ByGroups(UsingSelf("root"), Text), Push("endblock")},
+			// This seems to cause a recursive loop.
+			// {`(end)(\s+)`, ByGroups(UsingSelf("root"), Text), Push("endblock")},
+			{`(end)(\s+)`, ByGroups(Keyword, Text), Push("endblock")},
 			Include("types"),
 			Include("keywords"),
 			Include("numbers"),

mutators_test.go

@@ -3,8 +3,7 @@ package chroma
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
+	"github.com/alecthomas/assert"
 )
 
 func TestInclude(t *testing.T) {
@@ -18,7 +17,7 @@ func TestInclude(t *testing.T) {
 	}
 	lexer := &RegexLexer{rules: actual}
 	err := include.Mutator.(LexerMutator).MutateLexer(lexer.rules, "root", 0)
-	require.NoError(t, err)
+	assert.NoError(t, err)
 	expected := CompiledRules{
 		"root": {
 			{Rule: Rule{
@@ -41,18 +40,18 @@ func TestInclude(t *testing.T) {
 			}},
 		},
 	}
-	require.Equal(t, expected, actual)
+	assert.Equal(t, expected, actual)
 }
 
 func TestCombine(t *testing.T) {
-	l := MustNewLexer(nil, Rules{
+	l := MustNewLexer(&Config{DontEnsureNL: true}, Rules{
 		"root":  {{`hello`, String, Combined("world", "bye", "space")}},
 		"world": {{`world`, Name, nil}},
 		"bye":   {{`bye`, Name, nil}},
 		"space": {{`\s+`, Whitespace, nil}},
 	})
 	it, err := l.Tokenise(nil, "hello world")
-	require.NoError(t, err)
+	assert.NoError(t, err)
 	expected := []*Token{{String, `hello`}, {Whitespace, ` `}, {Name, `world`}}
 	assert.Equal(t, expected, it.Tokens())
 }

regexp.go

@@ -300,6 +300,9 @@ func (r *RegexLexer) Tokenise(options *TokeniseOptions, text string) (Iterator,
 	if options == nil {
 		options = defaultOptions
 	}
+	if !r.config.DontEnsureNL && !strings.HasSuffix(text, "\n") {
+		text += "\n"
+	}
 	state := &LexerState{
 		Lexer:          r,
 		Text:           []rune(text),

remap_test.go

@@ -3,11 +3,11 @@ package chroma
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/alecthomas/assert"
 )
 
 func TestRemappingLexer(t *testing.T) {
-	var lexer Lexer = MustNewLexer(nil, Rules{
+	var lexer Lexer = MustNewLexer(&Config{DontEnsureNL: true}, Rules{
 		"root": {
 			{`\s+`, Whitespace, nil},
 			{`\w+`, Name, nil},

style_test.go

@@ -3,7 +3,7 @@ package chroma
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/alecthomas/assert"
 )
 
 func TestStyleInherit(t *testing.T) {