Adding unit tests

internal/pkg/agent/install/progress.go

@@ -25,9 +25,9 @@ func (pt *ProgressTracker) StepStart(msg string) {
 }
 
 func (pt *ProgressTracker) StepSucceeded() {
-	fmt.Fprintln(pt.writer, "DONE")
+	fmt.Fprintln(pt.writer, " DONE")
 }
 
 func (pt *ProgressTracker) StepFailed() {
-	fmt.Fprintln(pt.writer, "FAILED")
+	fmt.Fprintln(pt.writer, " FAILED")
 }

internal/pkg/agent/install/progress_test.go

@@ -0,0 +1,50 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package install
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type testWriter struct {
+	buf []byte
+}
+
+func newTestWriter() *testWriter {
+	return &testWriter{
+		buf: []byte{},
+	}
+}
+
+func (tw *testWriter) Write(p []byte) (int, error) {
+	tw.buf = append(tw.buf, p...)
+	return len(p), nil
+}
+
+func TestProgress(t *testing.T) {
+	t.Run("single_step_immediate_failure", func(t *testing.T) {
+		w := newTestWriter()
+		pt := NewProgressTracker(w)
+
+		pt.StepStart("step 1 starting")
+		pt.StepFailed()
+
+		require.Equal(t, "step 1 starting... FAILED\n", string(w.buf))
+	})
+
+	t.Run("multi_step_success", func(t *testing.T) {
+		w := newTestWriter()
+		pt := NewProgressTracker(w)
+
+		pt.StepStart("step 1 starting")
+		pt.StepSucceeded()
+		pt.StepStart("step 2 starting")
+		pt.StepSucceeded()
+
+		require.Equal(t, "step 1 starting... DONE\nstep 2 starting... DONE\n", string(w.buf))
+	})
+}