diff --git a/genmanifest/genmanifest_test.go b/genmanifest/genmanifest_test.go
new file mode 100644
index 0000000..81b102f
--- /dev/null
+++ b/genmanifest/genmanifest_test.go
@@ -0,0 +1,79 @@
+package main
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
+	"io"
+	"os"
+	"testing"
+)
+
+type Manifest struct {
+	name         string
+	templateFile string
+	expectedFile string
+	dependencies []string
+}
+
+func TestManifestConversions(t *testing.T) {
+	testManifests := []Manifest{
+		{
+			name:         "ManifestSmall",
+			templateFile: "testdata/manifest_small1.gjson",
+			expectedFile: "testdata/manifest_small1_expected.json",
+			dependencies: []string{"AAA", "BBB", "D"},
+		},
+		{
+			name:         "ManifestFrozenChromium",
+			templateFile: "testdata/manifest_frozen.gjson",
+			expectedFile: "testdata/manifest_frozen_chromium_expected.json",
+			dependencies: []string{"CHROMIUM"},
+		},
+		{
+			name:         "ManifestFrozenGecko",
+			templateFile: "testdata/manifest_frozen.gjson",
+			expectedFile: "testdata/manifest_frozen_gecko_expected.json",
+			dependencies: []string{"GECKO"},
+		},
+	}
+
+	for _, m := range testManifests {
+		t.Run(m.name, func(t *testing.T) {
+			template, err := os.Open(m.templateFile)
+			if err != nil {
+				t.Fatalf("Can't open test file: %v", err)
+			}
+			defer template.Close()
+
+			expected, err := os.Open(m.expectedFile)
+			if err != nil {
+				t.Fatalf("Can't open expected file: %v", err)
+			}
+			defer expected.Close()
+
+			dest := bytes.NewBufferString("")
+
+			WriteManifest(template, dest, m.dependencies)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			h1 := sha256.New()
+			if _, err := io.Copy(h1, dest); err != nil {
+				t.Fatalf("Can't prepare sha256 sum of the result: %v", err)
+			}
+
+			h2 := sha256.New()
+			if _, err := io.Copy(h2, expected); err != nil {
+				t.Fatalf("Can't prepare sha256 sum of the expected file: %v", err)
+			}
+
+			sum1 := h1.Sum(nil)
+			sum2 := h2.Sum(nil)
+			if bytes.Compare(sum1, sum2) != 0 {
+				t.Fatalf("The expected manifest file (sha256: %v) differs from what we got (sha256: %v).", hex.EncodeToString(sum2), hex.EncodeToString(sum1))
+			}
+		})
+	}
+}