Rework kms folder structure

Signed-off-by: Daniel Weiße <dw@edgeless.systems>

kms/storage/memfsstroage_test.go

@@ -0,0 +1,39 @@
+package storage
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMemMapStorage(t *testing.T) {
+	assert := assert.New(t)
+
+	storage := NewMemMapStorage()
+
+	testDEK1 := []byte("test DEK")
+	testDEK2 := []byte("more test DEK")
+	ctx := context.Background()
+
+	// request unset value
+	_, err := storage.Get(ctx, "test:input")
+	assert.Error(err)
+
+	// test Put method
+	assert.NoError(storage.Put(ctx, "volume01", testDEK1))
+	assert.NoError(storage.Put(ctx, "volume02", testDEK2))
+
+	// make sure values have been set
+	val, err := storage.Get(ctx, "volume01")
+	assert.NoError(err)
+	assert.Equal(testDEK1, val)
+	val, err = storage.Get(ctx, "volume02")
+	assert.NoError(err)
+	assert.Equal(testDEK2, val)
+
+	_, err = storage.Get(ctx, "invalid:key")
+	assert.Error(err)
+	assert.True(errors.Is(err, ErrDEKUnset))
+}