diff --git a/ui/logger/logger_test.go b/ui/logger/logger_test.go
new file mode 100644
index 0000000..0f88ab3
--- /dev/null
+++ b/ui/logger/logger_test.go
@@ -0,0 +1,198 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package logger
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"reflect"
+	"sort"
+	"syscall"
+	"testing"
+)
+
+func TestCreateFileWithRotation(t *testing.T) {
+	dir, err := ioutil.TempDir("", "test-rotation")
+	if err != nil {
+		t.Fatalf("Failed to get TempDir: %v", err)
+	}
+	defer os.RemoveAll(dir)
+
+	file := filepath.Join(dir, "build.log")
+
+	writeFile := func(name string, data string) {
+		f, err := CreateFileWithRotation(name, 3)
+		if err != nil {
+			t.Fatalf("Failed to create file: %v", err)
+		}
+		if n, err := io.WriteString(f, data); err == nil && n < len(data) {
+			t.Fatalf("Short write")
+		} else if err != nil {
+			t.Fatalf("Failed to write: %v", err)
+		}
+		if err := f.Close(); err != nil {
+			t.Fatalf("Failed to close: %v", err)
+		}
+	}
+
+	writeFile(file, "a")
+	writeFile(file, "b")
+	writeFile(file, "c")
+	writeFile(file, "d")
+	writeFile(file, "e")
+
+	d, err := os.Open(dir)
+	if err != nil {
+		t.Fatalf("Failed to open dir: %v", err)
+	}
+	names, err := d.Readdirnames(0)
+	if err != nil {
+		t.Fatalf("Failed to read dir: %v", err)
+	}
+	sort.Strings(names)
+	expected := []string{"build.1.log", "build.2.log", "build.3.log", "build.log"}
+	if !reflect.DeepEqual(names, expected) {
+		t.Errorf("File list does not match.")
+		t.Errorf("     got: %v", names)
+		t.Errorf("expected: %v", expected)
+		t.FailNow()
+	}
+
+	expectFileContents := func(name, expected string) {
+		data, err := ioutil.ReadFile(filepath.Join(dir, name))
+		if err != nil {
+			t.Errorf("Error reading file: %v", err)
+			return
+		}
+		str := string(data)
+		if str != expected {
+			t.Errorf("Contents of %v does not match.", name)
+			t.Errorf("     got: %v", data)
+			t.Errorf("expected: %v", expected)
+		}
+	}
+
+	expectFileContents("build.log", "e")
+	expectFileContents("build.1.log", "d")
+	expectFileContents("build.2.log", "c")
+	expectFileContents("build.3.log", "b")
+}
+
+func TestPanic(t *testing.T) {
+	if os.Getenv("ACTUALLY_PANIC") == "1" {
+		panicValue := "foo"
+		log := New(&bytes.Buffer{})
+
+		defer func() {
+			p := recover()
+
+			if p == panicValue {
+				os.Exit(42)
+			} else {
+				fmt.Fprintln(os.Stderr, "Expected %q, got %v", panicValue, p)
+				os.Exit(3)
+			}
+		}()
+		defer log.Cleanup()
+
+		log.Panic(panicValue)
+		os.Exit(2)
+		return
+	}
+
+	// Run this in an external process so that we don't pollute stderr
+	cmd := exec.Command(os.Args[0], "-test.run=TestPanic")
+	cmd.Env = append(os.Environ(), "ACTUALLY_PANIC=1")
+	err := cmd.Run()
+	if e, ok := err.(*exec.ExitError); ok && e.Sys().(syscall.WaitStatus).ExitStatus() == 42 {
+		return
+	}
+	t.Errorf("Expected process to exit with status 42, got %v", err)
+}
+
+func TestFatal(t *testing.T) {
+	if os.Getenv("ACTUALLY_FATAL") == "1" {
+		log := New(&bytes.Buffer{})
+		defer func() {
+			// Shouldn't get here
+			os.Exit(3)
+		}()
+		defer log.Cleanup()
+		log.Fatal("Test")
+		os.Exit(0)
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestFatal")
+	cmd.Env = append(os.Environ(), "ACTUALLY_FATAL=1")
+	err := cmd.Run()
+	if e, ok := err.(*exec.ExitError); ok && e.Sys().(syscall.WaitStatus).ExitStatus() == 1 {
+		return
+	}
+	t.Errorf("Expected process to exit with status 1, got %v", err)
+}
+
+func TestNonFatal(t *testing.T) {
+	if os.Getenv("ACTUAL_TEST") == "1" {
+		log := New(&bytes.Buffer{})
+		defer log.Cleanup()
+		log.Println("Test")
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestNonFatal")
+	cmd.Env = append(os.Environ(), "ACTUAL_TEST=1")
+	err := cmd.Run()
+	if e, ok := err.(*exec.ExitError); ok || (ok && !e.Success()) {
+		t.Errorf("Expected process to exit cleanly, got %v", err)
+	}
+}
+
+func TestRecoverFatal(t *testing.T) {
+	log := New(&bytes.Buffer{})
+	defer func() {
+		if p := recover(); p != nil {
+			t.Errorf("Unexpected panic: %#v", p)
+		}
+	}()
+	defer Recover(func(err error) {
+		if err.Error() != "Test" {
+			t.Errorf("Expected %q, but got %q", "Test", err.Error())
+		}
+	})
+	log.Fatal("Test")
+	t.Errorf("Should not get here")
+}
+
+func TestRecoverNonFatal(t *testing.T) {
+	log := New(&bytes.Buffer{})
+	defer func() {
+		if p := recover(); p == nil {
+			t.Errorf("Panic not thrown")
+		} else if p != "Test" {
+			t.Errorf("Expected %q, but got %#v", "Test", p)
+		}
+	}()
+	defer Recover(func(err error) {
+		t.Errorf("Recover function should not be called")
+	})
+	log.Panic("Test")
+	t.Errorf("Should not get here")
+}