deploy: 06a1bdf735

vendor/gopl.io/ch11/echo/echo.go

@@ -0,0 +1,41 @@
+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+// See page 308.
+//!+
+
+// Echo prints its command-line arguments.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+var (
+	n = flag.Bool("n", false, "omit trailing newline")
+	s = flag.String("s", " ", "separator")
+)
+
+var out io.Writer = os.Stdout // modified during testing
+
+func main() {
+	flag.Parse()
+	if err := echo(!*n, *s, flag.Args()); err != nil {
+		fmt.Fprintf(os.Stderr, "echo: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func echo(newline bool, sep string, args []string) error {
+	fmt.Fprint(out, strings.Join(args, sep))
+	if newline {
+		fmt.Fprintln(out)
+	}
+	return nil
+}
+
+//!-

vendor/gopl.io/ch11/echo/echo_test.go

@@ -0,0 +1,45 @@
+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+// Test of echo command.  Run with: go test gopl.io/ch11/echo
+
+//!+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+)
+
+func TestEcho(t *testing.T) {
+	var tests = []struct {
+		newline bool
+		sep     string
+		args    []string
+		want    string
+	}{
+		{true, "", []string{}, "\n"},
+		{false, "", []string{}, ""},
+		{true, "\t", []string{"one", "two", "three"}, "one\ttwo\tthree\n"},
+		{true, ",", []string{"a", "b", "c"}, "a,b,c\n"},
+		{false, ":", []string{"1", "2", "3"}, "1:2:3"},
+	}
+
+	for _, test := range tests {
+		descr := fmt.Sprintf("echo(%v, %q, %q)",
+			test.newline, test.sep, test.args)
+
+		out = new(bytes.Buffer) // captured output
+		if err := echo(test.newline, test.sep, test.args); err != nil {
+			t.Errorf("%s failed: %v", descr, err)
+			continue
+		}
+		got := out.(*bytes.Buffer).String()
+		if got != test.want {
+			t.Errorf("%s = %q, want %q", descr, got, test.want)
+		}
+	}
+}
+
+//!-