diff --git a/go.mod b/go.mod
index 0915e02..684fa25 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,13 @@
 module git.jlel.se/jlelse/template-strings
 
-go 1.16
+go 1.17
 
-require gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
+require (
+	github.com/stretchr/testify v1.7.0
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+)
diff --git a/go.sum b/go.sum
index e387ff0..c221f64 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,13 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/templatestrings.go b/templatestrings.go
index 3c0673c..83ef8a1 100644
--- a/templatestrings.go
+++ b/templatestrings.go
@@ -2,6 +2,7 @@ package templatestrings
 
 import (
 	"errors"
+	"io/fs"
 	"os"
 	"path/filepath"
 
@@ -15,6 +16,11 @@ type TemplateStrings struct {
 
 // Load the strings from the specified files into memory
 func InitTemplateStrings(stringsDir string, fileExt string, defaultVariant string, otherVariants ...string) (*TemplateStrings, error) {
+	return InitTemplateStringsFS(os.DirFS("."), stringsDir, fileExt, defaultVariant, otherVariants...)
+}
+
+// Load the strings from the specified files using a file system into memory
+func InitTemplateStringsFS(filesystem fs.FS, stringsDir string, fileExt string, defaultVariant string, otherVariants ...string) (*TemplateStrings, error) {
 	ts := &TemplateStrings{
 		map[string]map[string]string{},
 		defaultVariant,
diff --git a/templatestrings_test.go b/templatestrings_test.go
index 214235b..f87bcfe 100644
--- a/templatestrings_test.go
+++ b/templatestrings_test.go
@@ -1,122 +1,91 @@
 package templatestrings
 
 import (
+	"embed"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
+//go:embed testdata/*
+var embeddedTestData embed.FS
+
 func TestAll(t *testing.T) {
 	t.Run("Faulty initialization", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata", ".yaml", "en", "faulty")
-		if err == nil {
-			t.Error()
-		}
+		require.Error(t, err)
 	})
 	t.Run("Missing dir", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata/x", ".yaml", "en")
-		if err == nil {
-			t.Error()
-		}
+		require.Error(t, err)
 	})
 	t.Run("Missing file", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata", ".yaml", "en", "x")
-		if err != nil {
-			t.Error()
-		}
+		require.NoError(t, err)
 	})
 	t.Run("File as directory", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata/en.yaml", ".yaml", "en")
-		if err == nil {
-			t.Error()
-		}
+		require.Error(t, err)
 	})
 	t.Run("Missing default variant", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata", ".yaml", "x", "en")
-		if err == nil {
-			t.Error()
-		}
+		require.Error(t, err)
 	})
 	t.Run("No variants", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata", ".yaml", "x")
-		if err == nil {
-			t.Error()
-		}
+		require.Error(t, err)
 	})
 	t.Run("Language twice", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata", ".yaml", "en", "en", "de")
-		if err != nil {
-			t.Error()
-		}
+		require.NoError(t, err)
 	})
 	t.Run("Empty language", func(t *testing.T) {
 		_, err := InitTemplateStrings("testdata", ".yaml", "")
-		if err == nil {
-			t.Error()
-		}
+		require.Error(t, err)
 	})
 	t.Run("Wrong number of inputs", func(t *testing.T) {
 		ts, err := InitTemplateStrings("testdata", ".yaml", "en", "de")
-		if err != nil {
-			t.FailNow()
-		}
-		if ts.GetTemplateStringVariant("simple", "en", "x") != "" {
-			t.Error()
-		}
+		require.NoError(t, err)
+		assert.Empty(t, ts.GetTemplateStringVariant("simple", "en", "x"))
 	})
 	t.Run("Default variant", func(t *testing.T) {
 		ts, err := InitTemplateStrings("testdata", ".yaml", "en", "de")
-		if err != nil {
-			t.FailNow()
-		}
-		if ts.GetTemplateStringVariant("simple") != "Simple" {
-			t.Error()
-		}
+		require.NoError(t, err)
+		assert.Equal(t, "Simple", ts.GetTemplateStringVariant("simple"))
 	})
 	t.Run("Specified variant", func(t *testing.T) {
 		ts, err := InitTemplateStrings("testdata", ".yaml", "en", "de")
-		if err != nil {
-			t.FailNow()
-		}
-		if ts.GetTemplateStringVariant("en", "simple") != "Simple" {
-			t.Error()
-		}
-		if ts.GetTemplateStringVariant("de", "simple") != "Einfach" {
-			t.Error()
-		}
+		require.NoError(t, err)
+		assert.Equal(t, "Simple", ts.GetTemplateStringVariant("en", "simple"))
+		assert.Equal(t, "Einfach", ts.GetTemplateStringVariant("de", "simple"))
 	})
 	t.Run("Fallback to default variant", func(t *testing.T) {
 		ts, err := InitTemplateStrings("testdata", ".yaml", "en", "de")
-		if err != nil {
-			t.FailNow()
-		}
-		if ts.GetTemplateStringVariant("de", "fallback") != "Fallback" {
-			t.Error()
-		}
+		require.NoError(t, err)
+		assert.Equal(t, "Fallback", ts.GetTemplateStringVariant("de", "fallback"))
 	})
 	t.Run("Missing variant", func(t *testing.T) {
 		ts, err := InitTemplateStrings("testdata", ".yaml", "en", "de")
-		if err != nil {
-			t.FailNow()
-		}
-		if ts.GetTemplateStringVariant("x", "simple") != "Simple" {
-			t.Error()
-		}
+		require.NoError(t, err)
+		assert.Equal(t, "Simple", ts.GetTemplateStringVariant("x", "simple"))
 	})
 	t.Run("Missing string", func(t *testing.T) {
 		ts, err := InitTemplateStrings("testdata", ".yaml", "en", "de")
-		if err != nil {
-			t.FailNow()
-		}
-		if ts.GetTemplateStringVariant("x") != "" {
-			t.Error()
-		}
+		require.NoError(t, err)
+		assert.Empty(t, ts.GetTemplateStringVariant("x"))
 	})
 	t.Run("Template func", func(t *testing.T) {
 		ts, err := InitTemplateStrings("testdata", ".yaml", "en", "de")
-		if err != nil {
-			t.FailNow()
-		}
-		if ts.GetTemplateStringVariantFunc()("simple") != "Simple" {
-			t.Error()
-		}
+		require.NoError(t, err)
+		assert.Equal(t, "Simple", ts.GetTemplateStringVariantFunc()("simple"))
+	})
+
+	// Test using embedded strings
+	t.Run("Specified variant", func(t *testing.T) {
+		ts, err := InitTemplateStringsFS(embeddedTestData, "testdata", ".yaml", "en", "de")
+		require.NoError(t, err)
+		assert.Equal(t, "Simple", ts.GetTemplateStringVariant("en", "simple"))
+		assert.Equal(t, "Einfach", ts.GetTemplateStringVariant("de", "simple"))
 	})
 }