1 files changed, 261 insertions, 0 deletions
diff --git a/src/testing/iotest/reader_test.go b/src/testing/iotest/reader_test.go
new file mode 100644
index 0000000..1d22237
--- /dev/null
+++ b/src/testing/iotest/reader_test.go
@@ -0,0 +1,261 @@
+// Copyright 2019 The Go 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 iotest
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"strings"
+	"testing"
+)
+
+func TestOneByteReader_nonEmptyReader(t *testing.T) {
+	msg := "Hello, World!"
+	buf := new(bytes.Buffer)
+	buf.WriteString(msg)
+
+	obr := OneByteReader(buf)
+	var b []byte
+	n, err := obr.Read(b)
+	if err != nil || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+
+	b = make([]byte, 3)
+	// Read from obr until EOF.
+	got := new(strings.Builder)
+	for i := 0; ; i++ {
+		n, err = obr.Read(b)
+		if err != nil {
+			break
+		}
+		if g, w := n, 1; g != w {
+			t.Errorf("Iteration #%d read %d bytes, want %d", i, g, w)
+		}
+		got.Write(b[:n])
+	}
+	if g, w := err, io.EOF; g != w {
+		t.Errorf("Unexpected error after reading all bytes\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := got.String(), "Hello, World!"; g != w {
+		t.Errorf("Read mismatch\n\tGot:  %q\n\tWant: %q", g, w)
+	}
+}
+
+func TestOneByteReader_emptyReader(t *testing.T) {
+	r := new(bytes.Buffer)
+
+	obr := OneByteReader(r)
+	var b []byte
+	if n, err := obr.Read(b); err != nil || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+
+	b = make([]byte, 5)
+	n, err := obr.Read(b)
+	if g, w := err, io.EOF; g != w {
+		t.Errorf("Error mismatch\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := n, 0; g != w {
+		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
+	}
+}
+
+func TestHalfReader_nonEmptyReader(t *testing.T) {
+	msg := "Hello, World!"
+	buf := new(bytes.Buffer)
+	buf.WriteString(msg)
+	// empty read buffer
+	hr := HalfReader(buf)
+	var b []byte
+	n, err := hr.Read(b)
+	if err != nil || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+	// non empty read buffer
+	b = make([]byte, 2)
+	got := new(strings.Builder)
+	for i := 0; ; i++ {
+		n, err = hr.Read(b)
+		if err != nil {
+			break
+		}
+		if g, w := n, 1; g != w {
+			t.Errorf("Iteration #%d read %d bytes, want %d", i, g, w)
+		}
+		got.Write(b[:n])
+	}
+	if g, w := err, io.EOF; g != w {
+		t.Errorf("Unexpected error after reading all bytes\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := got.String(), "Hello, World!"; g != w {
+		t.Errorf("Read mismatch\n\tGot:  %q\n\tWant: %q", g, w)
+	}
+}
+
+func TestHalfReader_emptyReader(t *testing.T) {
+	r := new(bytes.Buffer)
+
+	hr := HalfReader(r)
+	var b []byte
+	if n, err := hr.Read(b); err != nil || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+
+	b = make([]byte, 5)
+	n, err := hr.Read(b)
+	if g, w := err, io.EOF; g != w {
+		t.Errorf("Error mismatch\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := n, 0; g != w {
+		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
+	}
+}
+
+func TestTimeOutReader_nonEmptyReader(t *testing.T) {
+	msg := "Hello, World!"
+	buf := new(bytes.Buffer)
+	buf.WriteString(msg)
+	// empty read buffer
+	tor := TimeoutReader(buf)
+	var b []byte
+	n, err := tor.Read(b)
+	if err != nil || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+	// Second call should timeout
+	n, err = tor.Read(b)
+	if g, w := err, ErrTimeout; g != w {
+		t.Errorf("Error mismatch\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := n, 0; g != w {
+		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
+	}
+	// non empty read buffer
+	tor2 := TimeoutReader(buf)
+	b = make([]byte, 3)
+	if n, err := tor2.Read(b); err != nil || n == 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+	// Second call should timeout
+	n, err = tor2.Read(b)
+	if g, w := err, ErrTimeout; g != w {
+		t.Errorf("Error mismatch\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := n, 0; g != w {
+		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
+	}
+}
+
+func TestTimeOutReader_emptyReader(t *testing.T) {
+	r := new(bytes.Buffer)
+	// empty read buffer
+	tor := TimeoutReader(r)
+	var b []byte
+	if n, err := tor.Read(b); err != nil || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+	// Second call should timeout
+	n, err := tor.Read(b)
+	if g, w := err, ErrTimeout; g != w {
+		t.Errorf("Error mismatch\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := n, 0; g != w {
+		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
+	}
+	// non empty read buffer
+	tor2 := TimeoutReader(r)
+	b = make([]byte, 5)
+	if n, err := tor2.Read(b); err != io.EOF || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+	// Second call should timeout
+	n, err = tor2.Read(b)
+	if g, w := err, ErrTimeout; g != w {
+		t.Errorf("Error mismatch\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := n, 0; g != w {
+		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
+	}
+}
+
+func TestDataErrReader_nonEmptyReader(t *testing.T) {
+	msg := "Hello, World!"
+	buf := new(bytes.Buffer)
+	buf.WriteString(msg)
+
+	der := DataErrReader(buf)
+
+	b := make([]byte, 3)
+	got := new(strings.Builder)
+	var n int
+	var err error
+	for {
+		n, err = der.Read(b)
+		got.Write(b[:n])
+		if err != nil {
+			break
+		}
+	}
+	if err != io.EOF || n == 0 {
+		t.Errorf("Last Read returned n=%d err=%v", n, err)
+	}
+	if g, w := got.String(), "Hello, World!"; g != w {
+		t.Errorf("Read mismatch\n\tGot:  %q\n\tWant: %q", g, w)
+	}
+}
+
+func TestDataErrReader_emptyReader(t *testing.T) {
+	r := new(bytes.Buffer)
+
+	der := DataErrReader(r)
+	var b []byte
+	if n, err := der.Read(b); err != io.EOF || n != 0 {
+		t.Errorf("Empty buffer read returned n=%d err=%v", n, err)
+	}
+
+	b = make([]byte, 5)
+	n, err := der.Read(b)
+	if g, w := err, io.EOF; g != w {
+		t.Errorf("Error mismatch\n\tGot:  %v\n\tWant: %v", g, w)
+	}
+	if g, w := n, 0; g != w {
+		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
+	}
+}
+
+func TestErrReader(t *testing.T) {
+	cases := []struct {
+		name string
+		err  error
+	}{
+		{"nil error", nil},
+		{"non-nil error", errors.New("io failure")},
+		{"io.EOF", io.EOF},
+	}
+
+	for _, tt := range cases {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			n, err := ErrReader(tt.err).Read(nil)
+			if err != tt.err {
+				t.Fatalf("Error mismatch\nGot:  %v\nWant: %v", err, tt.err)
+			}
+			if n != 0 {
+				t.Fatalf("Byte count mismatch: got %d want 0", n)
+			}
+		})
+	}
+}
+
+func TestStringsReader(t *testing.T) {
+	const msg = "Now is the time for all good gophers."
+
+	r := strings.NewReader(msg)
+	if err := TestReader(r, []byte(msg)); err != nil {
+		t.Fatal(err)
+	}
+}