diff --git a/hcl2template/formatter_test.go b/hcl2template/formatter_test.go
index 36067f29e..139308882 100644
--- a/hcl2template/formatter_test.go
+++ b/hcl2template/formatter_test.go
@@ -2,7 +2,13 @@ package hcl2template
 
 import (
 	"bytes"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"strings"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestHCL2Formatter_Format(t *testing.T) {
@@ -31,3 +37,73 @@ func TestHCL2Formatter_Format(t *testing.T) {
 		}
 	}
 }
+
+func TestHCL2Formatter_Format_Write(t *testing.T) {
+
+	var buf bytes.Buffer
+	f := NewHCL2Formatter()
+	f.Output = &buf
+	f.Write = true
+
+	unformattedData, err := ioutil.ReadFile("testdata/format/unformatted.pkr.hcl")
+	if err != nil {
+		t.Fatalf("failed to open the unformatted fixture %s", err)
+	}
+
+	tf, err := ioutil.TempFile("", "*.pkr.hcl")
+	if err != nil {
+		t.Fatalf("failed to create tempfile for test %s", err)
+	}
+	defer os.Remove(tf.Name())
+
+	_, _ = tf.Write(unformattedData)
+	tf.Close()
+
+	_, diags := f.Format(tf.Name())
+	if diags.HasErrors() {
+		t.Fatalf("the call to Format failed unexpectedly %s", diags.Error())
+	}
+
+	//lets re-read the tempfile which should now be formatted
+	data, err := ioutil.ReadFile(tf.Name())
+	if err != nil {
+		t.Fatalf("failed to open the newly formatted fixture %s", err)
+	}
+
+	formattedData, err := ioutil.ReadFile("testdata/format/formatted.pkr.hcl")
+	if err != nil {
+		t.Fatalf("failed to open the formatted fixture %s", err)
+	}
+
+	if diff := cmp.Diff(string(data), string(formattedData)); diff != "" {
+		t.Errorf("Unexpected format output %s", diff)
+	}
+}
+
+func TestHCL2Formatter_Format_ShowDiff(t *testing.T) {
+
+	if _, err := exec.LookPath("diff"); err != nil {
+		t.Skip("Skipping test because diff is not in the executable PATH")
+	}
+
+	var buf bytes.Buffer
+	f := HCL2Formatter{
+		Output:   &buf,
+		ShowDiff: true,
+	}
+
+	_, diags := f.Format("testdata/format/unformatted.pkr.hcl")
+	if diags.HasErrors() {
+		t.Fatalf("the call to Format failed unexpectedly %s", diags.Error())
+	}
+
+	diffHeader := `
+--- old/testdata/format/unformatted.pkr.hcl
++++ new/testdata/format/unformatted.pkr.hcl
+@@ -1,149 +1,149 @@
+`
+	if !strings.Contains(buf.String(), diffHeader) {
+		t.Errorf("expected buf to contain a file diff, but instead we got %s", buf.String())
+	}
+
+}