t.Fatalf("envelopeTransformer transformed data incorrectly. Expected: %v, got %v", originalText, untransformedData)
			}

			// advance the clock to allow cache entries to expire depending on TTL
			fakeClock.Step(2 * time.Minute)
			// force GC to run by performing a write
			transformer.(*envelopeTransformer).cache.set([]byte("some-other-unrelated-key"), &envelopeTransformer{})

	tests := []struct {
		name        string
		key         []byte
		transformer value.Transformer
	}{
		{
			name:        "empty key",
			key:         []byte{},
			transformer: &envelopeTransformer{},
		},
		{
			name:        "nil transformer",
			key:         []byte("key"),
			transformer: nil,
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			defer func() {

	return &envelopeTransformer{
		envelopeService: envelopeService,
		providerName:    providerName,
		stateFunc:       stateFunc,
		cache:           newSimpleCache(clock, cacheTTL, providerName),
		apiServerID:     apiServerID,
	}
}

// TransformFromStorage decrypts data encrypted by this transformer using envelope encryption.