Merge pull request #263 from dedis/inmemory_store

More realistic fake.InMemorySnapshot

contracts/value/value_test.go

@@ -144,7 +144,7 @@ func TestCommand_Delete(t *testing.T) {
 
 	res, err := snap.Get(key)
 	require.Nil(t, err)
-	require.Nil(t, res)
+	require.Nil(t, res) // = "key not found"
 
 	_, found := contract.index[keyStr]
 	require.False(t, found)

core/access/darc/darc.go

@@ -4,16 +4,15 @@
 package darc
 
 import (
+	contract "go.dedis.ch/dela/contracts/access"
 	"go.dedis.ch/dela/core/access"
 	"go.dedis.ch/dela/core/access/darc/types"
 	"go.dedis.ch/dela/core/store"
+	"go.dedis.ch/dela/core/store/prefixed"
 	"go.dedis.ch/dela/serde"
 	"golang.org/x/xerrors"
 )
 
-// 4 bytes used to prefix DARC keys in the K/V store.
-const ContractUID = "DARC"
-
 // Service is an implementation of an access service that will allow one to
 // store and verify access for a group of identities.
 //
@@ -39,6 +38,7 @@ func (srvc Service) Match(
 	creds access.Credential,
 	idents ...access.Identity,
 ) error {
+	store = prefixed.NewReadable(contract.ContractUID, store)
 	perm, err := srvc.readPermission(store, creds.GetID())
 	if err != nil {
 		return xerrors.Errorf("store failed: %v", err)
@@ -63,6 +63,8 @@ func (srvc Service) Grant(
 	cred access.Credential,
 	idents ...access.Identity,
 ) error {
+	store = prefixed.NewSnapshot(contract.ContractUID, store)
+
 	perm, err := srvc.readPermission(store, cred.GetID())
 	if err != nil {
 		return xerrors.Errorf("store failed: %v", err)

core/access/darc/darc_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+	contract "go.dedis.ch/dela/contracts/access"
 	"go.dedis.ch/dela/core/access"
 	"go.dedis.ch/dela/core/access/darc/types"
 	"go.dedis.ch/dela/core/store/prefixed"
@@ -16,22 +17,21 @@ import (
 var testCtx = json.NewContext()
 
 func TestService_Match(t *testing.T) {
-	store := prefixed.NewSnapshot(ContractUID, fake.NewSnapshot())
+	store := fake.NewSnapshot()
 
 	alice := bls.NewSigner()
 	bob := bls.NewSigner()
 
-	creds := access.NewContractCreds([]byte{'A'}, "test", "match")
+	creds := access.NewContractCreds([]byte{0xaa}, "test", "match")
 
 	perm := types.NewPermission()
 	perm.Allow(creds.GetRule(), alice.GetPublicKey())
 	data, err := perm.Serialize(testCtx)
 	require.NoError(t, err)
 
-	err = store.Set([]byte{'A'}, data)
-	require.NoError(t, err)
-	err = store.Set([]byte{'B'}, []byte{})
-	require.NoError(t, err)
+	prefixStore := prefixed.NewSnapshot(contract.ContractUID, store)
+	prefixStore.Set([]byte{0xaa}, data)
+	prefixStore.Set([]byte{0xbb}, []byte{})
 
 	srvc := NewService(testCtx)
 
@@ -47,51 +47,48 @@ func TestService_Match(t *testing.T) {
 	require.Regexp(t,
 		"^permission: rule 'test:match': unauthorized: \\[bls:[[:xdigit:]]+\\]", err.Error())
 
-	badStore := prefixed.NewSnapshot(ContractUID, fake.NewBadSnapshot())
-	err = srvc.Match(badStore, creds, alice.GetPublicKey())
+	err = srvc.Match(fake.NewBadSnapshot(), creds, alice.GetPublicKey())
 	require.EqualError(t, err, fake.Err("store failed: while reading"))
 
-	err = srvc.Match(store, access.NewContractCreds([]byte{'C'}, "", ""))
-	require.EqualError(t, err, "permission 0x43 not found")
+	err = srvc.Match(store, access.NewContractCreds([]byte{0xcc}, "", ""))
+	require.EqualError(t, err, "permission 0xcc not found")
 
-	err = srvc.Match(store, access.NewContractCreds([]byte{'B'}, "", ""), alice.GetPublicKey())
+	err = srvc.Match(store, access.NewContractCreds([]byte{0xbb}, "", ""), alice.GetPublicKey())
 	require.EqualError(t, err,
 		"store failed: permission malformed: JSON format: failed to unmarshal: unexpected end of JSON input")
 }
 
 func TestService_Grant(t *testing.T) {
-	store := prefixed.NewSnapshot(ContractUID, fake.NewSnapshot())
-	err := store.Set([]byte{'B'}, []byte{})
-	require.NoError(t, err)
+	store := fake.NewSnapshot()
+	prefixStore := prefixed.NewSnapshot(contract.ContractUID, store)
+	prefixStore.Set([]byte{0xbb}, []byte{})
 
-	creds := access.NewContractCreds([]byte{'A'}, "test", "grant")
+	creds := access.NewContractCreds([]byte{0xaa}, "test", "grant")
 
 	alice := bls.NewSigner()
 	bob := bls.NewSigner()
 
 	srvc := NewService(testCtx)
 
-	err = srvc.Grant(store, creds, alice.GetPublicKey())
+	err := srvc.Grant(store, creds, alice.GetPublicKey())
 	require.NoError(t, err)
 
 	err = srvc.Grant(store, creds, bob.GetPublicKey())
 	require.NoError(t, err)
 
-	badStore := prefixed.NewSnapshot(ContractUID, fake.NewBadSnapshot())
-	err = srvc.Grant(badStore, creds)
+	err = srvc.Grant(fake.NewBadSnapshot(), creds)
 	require.EqualError(t, err, fake.Err("store failed: while reading"))
 
-	err = srvc.Grant(store, access.NewContractCreds([]byte{'B'}, "", ""))
+	err = srvc.Grant(store, access.NewContractCreds([]byte{0xbb}, "", ""))
 	require.EqualError(t, err,
 		"store failed: permission malformed: JSON format: failed to unmarshal: unexpected end of JSON input")
 
 	srvc.fac = badFac{}
 	err = srvc.Grant(store, creds, alice.GetPublicKey())
 	require.EqualError(t, err, fake.Err("failed to serialize"))
 
-	fakeSnap := fake.NewSnapshot()
-	fakeSnap.ErrWrite = fake.GetError()
-	badStore = prefixed.NewSnapshot(ContractUID, fakeSnap)
+	badStore := fake.NewSnapshot()
+	badStore.ErrWrite = fake.GetError()
 	err = srvc.Grant(badStore, creds, alice.GetPublicKey())
 	require.EqualError(t, err, fake.Err("store failed to write"))
 }

core/store/prefixed/prefixed.go

@@ -22,7 +22,7 @@ type snapshot struct {
 	*readable
 }
 
-// NewSnapShot creates a new prefixed Snapshot.
+// NewSnapshot creates a new prefixed Snapshot.
 func NewSnapshot(prefix string, snap store.Snapshot) store.Snapshot {
 	p := []byte(prefix)
 	return &snapshot{
@@ -31,6 +31,12 @@ func NewSnapshot(prefix string, snap store.Snapshot) store.Snapshot {
 	}
 }
 
+// NewReadable creates a new prefixed Readable.
+func NewReadable(prefix string, r store.Readable) store.Readable {
+	p := []byte(prefix)
+	return &readable{r, p}
+}
+
 // Get implements store.Readable
 // It takes a key as input and returns a value or error status
 func (s *readable) Get(key []byte) ([]byte, error) {

core/store/store.go

@@ -12,6 +12,9 @@ type Readable interface {
 type Writable interface {
 	Set(key []byte, value []byte) error
 
+	// Delete deletes a given key.
+	// It can return an error if deleting from a read-only store
+	// No error is returned if the key does not exist.
 	Delete(key []byte) error
 }
 

testing/fake/store.go

@@ -36,21 +36,37 @@ func NewBadSnapshot() *InMemorySnapshot {
 
 // Get implements store.Snapshot.
 func (snap *InMemorySnapshot) Get(key []byte) ([]byte, error) {
-	return snap.values[string(key)], snap.ErrRead
+	if snap.ErrRead != nil {
+		return nil, snap.ErrRead
+	}
+
+	value, found := snap.values[string(key)]
+	if found {
+		return value, nil
+	}
+	return nil, nil
 }
 
 // Set implements store.Snapshot.
 func (snap *InMemorySnapshot) Set(key, value []byte) error {
+	if snap.ErrWrite != nil {
+		return snap.ErrWrite
+	}
+
 	snap.values[string(key)] = value
 
-	return snap.ErrWrite
+	return nil
 }
 
 // Delete implements store.Snapshot.
 func (snap *InMemorySnapshot) Delete(key []byte) error {
+	if snap.ErrDelete != nil {
+		return snap.ErrDelete
+	}
+
 	delete(snap.values, string(key))
 
-	return snap.ErrDelete
+	return nil
 }
 
 // InMemoryDB is a fake implementation of a key/value storage.