improve testability

.travis.yml

@@ -1,5 +1,5 @@
 language: go
 
 script:
- - go test -v
+ - go test -cover -v . ./cmd/gocha
  - go test -bench .

cmd/gocha/cli.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/t-mrt/gocha"
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+const (
+	ExitCodeOK = iota
+	ExitCodeError
+)
+
+type CLI struct {
+	outStream io.Writer
+	errStream io.Writer
+}
+
+func (c *CLI) Run(args []string) int {
+	var app = kingpin.New("gocha", "Random strings generater based on a pattern.")
+
+	var pattern = app.Arg("pattern", "Regular expression").Required().String()
+	var num = app.Flag("number-of-lines", "Number of lines").Short('n').Int()
+
+	var exitCode int
+	kingpin.CommandLine.Writer(c.errStream).Terminate(func(i int) {
+		exitCode = i
+	})
+	kingpin.MustParse(app.Parse(args[1:]))
+
+	if exitCode == ExitCodeError {
+		return ExitCodeError
+	}
+
+	err, g := gocha.New(*pattern)
+
+	if err != nil {
+		fmt.Fprintf(c.errStream, "gocha: %v\n", err.Error())
+		return ExitCodeError
+	}
+
+	if *num <= 0 {
+		*num = 1
+	}
+
+	for i := 0; i < *num; i++ {
+		fmt.Fprintln(c.outStream, g.Gen())
+	}
+
+	return ExitCodeOK
+}

cmd/gocha/cli_test.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestRun(t *testing.T) {
+	t.Run("ExitCodeOK", func(t *testing.T) {
+		outStream, errStream := new(bytes.Buffer), new(bytes.Buffer)
+		cli := &CLI{outStream: outStream, errStream: errStream}
+		args := strings.Split("gocha -n 1 '[a]{3}'", " ")
+		status := cli.Run(args)
+
+		if status != ExitCodeOK {
+			t.Errorf("ExitStatus=%d, want %d", status, ExitCodeOK)
+		}
+
+		expected := fmt.Sprintf("")
+		if errStream.String() != expected {
+			t.Errorf("Output=%q, want %q", errStream.String(), expected)
+		}
+
+		expected = fmt.Sprintf("'aaa'\n")
+		if outStream.String() != expected {
+			t.Errorf("Output=%q, want %q", outStream.String(), expected)
+		}
+	})
+
+	t.Run("ExitCodeError", func(t *testing.T) {
+		outStream, errStream := new(bytes.Buffer), new(bytes.Buffer)
+		cli := &CLI{outStream: outStream, errStream: errStream}
+		args := strings.Split("gocha -n 1 '.{100000}'", " ")
+		status := cli.Run(args)
+
+		if status != ExitCodeError {
+			t.Errorf("ExitStatus=%d, want %d", status, ExitCodeOK)
+		}
+
+		expected := fmt.Sprintf("gocha: error parsing regexp: invalid repeat count: `{100000}`\n")
+		if errStream.String() != expected {
+			t.Errorf("Output=%q, want %q", errStream.String(), expected)
+		}
+
+		expected = fmt.Sprintf("")
+		if outStream.String() != expected {
+			t.Errorf("Output=%q, want %q", outStream.String(), expected)
+		}
+	})
+
+	t.Run("RequirePattern", func(t *testing.T) {
+		outStream, errStream := new(bytes.Buffer), new(bytes.Buffer)
+		cli := &CLI{outStream: outStream, errStream: errStream}
+		args := strings.Split("gocha -n 1", " ")
+		status := cli.Run(args)
+
+		if status != ExitCodeError {
+			t.Errorf("ExitStatus=%d, want %d", status, ExitCodeError)
+		}
+
+		expected := fmt.Sprintf("gocha.test: error: required argument 'pattern' not provided, try --help\n")
+		if errStream.String() != expected {
+			t.Errorf("Output=%q, want %q", errStream.String(), expected)
+		}
+
+		expected = fmt.Sprintf("")
+		if outStream.String() != expected {
+			t.Errorf("Output=%q, want %q", outStream.String(), expected)
+		}
+	})
+}

cmd/gocha/main.go

@@ -1,47 +1,6 @@
 package main
 
-import (
-	"fmt"
-	"io"
-	"os"
-
-	"github.com/t-mrt/gocha"
-	"gopkg.in/alecthomas/kingpin.v2"
-)
-
-const (
-	ExitCodeOK = iota
-	ExitCodeError
-)
-
-type CLI struct {
-	outStream io.Writer
-	errStream io.Writer
-}
-
-func (c *CLI) Run(args []string) int {
-
-	var pattern = kingpin.Arg("pattern", "Regular expression").Required().String()
-	var num = kingpin.Flag("number-of-lines", "Number of lines").Short('n').Int()
-	kingpin.Parse()
-
-	err, g := gocha.New(*pattern)
-
-	if err != nil {
-		fmt.Fprintln(c.outStream, "gocha: error: Invalid regular expression")
-		return ExitCodeError
-	}
-
-	if *num <= 0 {
-		*num = 1
-	}
-
-	for i := 0; i < *num; i++ {
-		fmt.Fprintln(c.outStream, g.Gen())
-	}
-
-	return ExitCodeOK
-}
+import "os"
 
 func main() {
 	cli := &CLI{outStream: os.Stdout, errStream: os.Stderr}