ethdb/dbtest: addd test suite for ethdb backends (#19960)

- Move the existing tests from memorydb into a generalized testsuite
that can be run by any ethdb backend implementation.
- Add several more test cases to clarify some non-obvious nuances when
implementing a custom ethdb backend, such as the behaviour of
NewIteratorWithPrefix vs NewIteratorWithStart.
- Add leveldb to the testsuite using in-memory storage for fast
execution.

3 files changed, 364 insertions, 77 deletions

diff --git a/ethdb/dbtest/testsuite.go b/ethdb/dbtest/testsuite.go
new file mode 100644
index 000000000..dce2ba2a1
--- /dev/null
+++ b/ethdb/dbtest/testsuite.go
@@ -0,0 +1,315 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package dbtest
+
+import (
+	"bytes"
+	"reflect"
+	"sort"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/ethdb"
+)
+
+// TestDatabaseSuite runs a suite of tests against a KeyValueStore database
+// implementation.
+func TestDatabaseSuite(t *testing.T, New func() ethdb.KeyValueStore) {
+	t.Run("Iterator", func(t *testing.T) {
+		tests := []struct {
+			content map[string]string
+			prefix  string
+			order   []string
+		}{
+			// Empty databases should be iterable
+			{map[string]string{}, "", nil},
+			{map[string]string{}, "non-existent-prefix", nil},
+
+			// Single-item databases should be iterable
+			{map[string]string{"key": "val"}, "", []string{"key"}},
+			{map[string]string{"key": "val"}, "k", []string{"key"}},
+			{map[string]string{"key": "val"}, "l", nil},
+
+			// Multi-item databases should be fully iterable
+			{
+				map[string]string{"k1": "v1", "k5": "v5", "k2": "v2", "k4": "v4", "k3": "v3"},
+				"",
+				[]string{"k1", "k2", "k3", "k4", "k5"},
+			},
+			{
+				map[string]string{"k1": "v1", "k5": "v5", "k2": "v2", "k4": "v4", "k3": "v3"},
+				"k",
+				[]string{"k1", "k2", "k3", "k4", "k5"},
+			},
+			{
+				map[string]string{"k1": "v1", "k5": "v5", "k2": "v2", "k4": "v4", "k3": "v3"},
+				"l",
+				nil,
+			},
+			// Multi-item databases should be prefix-iterable
+			{
+				map[string]string{
+					"ka1": "va1", "ka5": "va5", "ka2": "va2", "ka4": "va4", "ka3": "va3",
+					"kb1": "vb1", "kb5": "vb5", "kb2": "vb2", "kb4": "vb4", "kb3": "vb3",
+				},
+				"ka",
+				[]string{"ka1", "ka2", "ka3", "ka4", "ka5"},
+			},
+			{
+				map[string]string{
+					"ka1": "va1", "ka5": "va5", "ka2": "va2", "ka4": "va4", "ka3": "va3",
+					"kb1": "vb1", "kb5": "vb5", "kb2": "vb2", "kb4": "vb4", "kb3": "vb3",
+				},
+				"kc",
+				nil,
+			},
+		}
+		for i, tt := range tests {
+			// Create the key-value data store
+			db := New()
+			for key, val := range tt.content {
+				if err := db.Put([]byte(key), []byte(val)); err != nil {
+					t.Fatalf("test %d: failed to insert item %s:%s into database: %v", i, key, val, err)
+				}
+			}
+			// Iterate over the database with the given configs and verify the results
+			it, idx := db.NewIteratorWithPrefix([]byte(tt.prefix)), 0
+			for it.Next() {
+				if len(tt.order) <= idx {
+					t.Errorf("test %d: prefix=%q more items than expected: checking idx=%d (key %q), expecting len=%d", i, tt.prefix, idx, it.Key(), len(tt.order))
+					break
+				}
+				if !bytes.Equal(it.Key(), []byte(tt.order[idx])) {
+					t.Errorf("test %d: item %d: key mismatch: have %s, want %s", i, idx, string(it.Key()), tt.order[idx])
+				}
+				if !bytes.Equal(it.Value(), []byte(tt.content[tt.order[idx]])) {
+					t.Errorf("test %d: item %d: value mismatch: have %s, want %s", i, idx, string(it.Value()), tt.content[tt.order[idx]])
+				}
+				idx++
+			}
+			if err := it.Error(); err != nil {
+				t.Errorf("test %d: iteration failed: %v", i, err)
+			}
+			if idx != len(tt.order) {
+				t.Errorf("test %d: iteration terminated prematurely: have %d, want %d", i, idx, len(tt.order))
+			}
+			db.Close()
+		}
+	})
+
+	t.Run("IteratorWith", func(t *testing.T) {
+		db := New()
+		defer db.Close()
+
+		keys := []string{"1", "2", "3", "4", "6", "10", "11", "12", "20", "21", "22"}
+		sort.Strings(keys) // 1, 10, 11, etc
+
+		for _, k := range keys {
+			if err := db.Put([]byte(k), nil); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		{
+			it := db.NewIterator()
+			got, want := iterateKeys(it), keys
+			if err := it.Error(); err != nil {
+				t.Fatal(err)
+			}
+			it.Release()
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("Iterator: got: %s; want: %s", got, want)
+			}
+		}
+
+		{
+			it := db.NewIteratorWithPrefix([]byte("1"))
+			got, want := iterateKeys(it), []string{"1", "10", "11", "12"}
+			if err := it.Error(); err != nil {
+				t.Fatal(err)
+			}
+			it.Release()
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("IteratorWithPrefix(1): got: %s; want: %s", got, want)
+			}
+		}
+
+		{
+			it := db.NewIteratorWithPrefix([]byte("5"))
+			got, want := iterateKeys(it), []string{}
+			if err := it.Error(); err != nil {
+				t.Fatal(err)
+			}
+			it.Release()
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("IteratorWithPrefix(1): got: %s; want: %s", got, want)
+			}
+		}
+
+		{
+			it := db.NewIteratorWithStart([]byte("2"))
+			got, want := iterateKeys(it), []string{"2", "20", "21", "22", "3", "4", "6"}
+			if err := it.Error(); err != nil {
+				t.Fatal(err)
+			}
+			it.Release()
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("IteratorWithStart(2): got: %s; want: %s", got, want)
+			}
+		}
+
+		{
+			it := db.NewIteratorWithStart([]byte("5"))
+			got, want := iterateKeys(it), []string{"6"}
+			if err := it.Error(); err != nil {
+				t.Fatal(err)
+			}
+			it.Release()
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("IteratorWithStart(2): got: %s; want: %s", got, want)
+			}
+		}
+	})
+
+	t.Run("KeyValueOperations", func(t *testing.T) {
+		db := New()
+		defer db.Close()
+
+		key := []byte("foo")
+
+		if got, err := db.Has(key); err != nil {
+			t.Error(err)
+		} else if got {
+			t.Errorf("wrong value: %t", got)
+		}
+
+		value := []byte("hello world")
+		if err := db.Put(key, value); err != nil {
+			t.Error(err)
+		}
+
+		if got, err := db.Has(key); err != nil {
+			t.Error(err)
+		} else if !got {
+			t.Errorf("wrong value: %t", got)
+		}
+
+		if got, err := db.Get(key); err != nil {
+			t.Error(err)
+		} else if !bytes.Equal(got, value) {
+			t.Errorf("wrong value: %q", got)
+		}
+
+		if err := db.Delete(key); err != nil {
+			t.Error(err)
+		}
+
+		if got, err := db.Has(key); err != nil {
+			t.Error(err)
+		} else if got {
+			t.Errorf("wrong value: %t", got)
+		}
+	})
+
+	t.Run("Batch", func(t *testing.T) {
+		db := New()
+		defer db.Close()
+
+		b := db.NewBatch()
+		for _, k := range []string{"1", "2", "3", "4"} {
+			if err := b.Put([]byte(k), nil); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		if has, err := db.Has([]byte("1")); err != nil {
+			t.Fatal(err)
+		} else if has {
+			t.Error("db contains element before batch write")
+		}
+
+		if err := b.Write(); err != nil {
+			t.Fatal(err)
+		}
+
+		{
+			it := db.NewIterator()
+			if got, want := iterateKeys(it), []string{"1", "2", "3", "4"}; !reflect.DeepEqual(got, want) {
+				t.Errorf("got: %s; want: %s", got, want)
+			}
+			it.Release()
+		}
+
+		b.Reset()
+
+		// Mix writes and deletes in batch
+		b.Put([]byte("5"), nil)
+		b.Delete([]byte("1"))
+		b.Put([]byte("6"), nil)
+		b.Delete([]byte("3"))
+		b.Put([]byte("3"), nil)
+
+		if err := b.Write(); err != nil {
+			t.Fatal(err)
+		}
+
+		{
+			it := db.NewIterator()
+			if got, want := iterateKeys(it), []string{"2", "3", "4", "5", "6"}; !reflect.DeepEqual(got, want) {
+				t.Errorf("got: %s; want: %s", got, want)
+			}
+			it.Release()
+		}
+	})
+
+	t.Run("BatchReplay", func(t *testing.T) {
+		db := New()
+		defer db.Close()
+
+		want := []string{"1", "2", "3", "4"}
+		b := db.NewBatch()
+		for _, k := range want {
+			if err := b.Put([]byte(k), nil); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		b2 := db.NewBatch()
+		if err := b.Replay(b2); err != nil {
+			t.Fatal(err)
+		}
+
+		if err := b2.Replay(db); err != nil {
+			t.Fatal(err)
+		}
+
+		it := db.NewIterator()
+		if got := iterateKeys(it); !reflect.DeepEqual(got, want) {
+			t.Errorf("got: %s; want: %s", got, want)
+		}
+		it.Release()
+	})
+
+}
+
+func iterateKeys(it ethdb.Iterator) []string {
+	keys := []string{}
+	for it.Next() {
+		keys = append(keys, string(it.Key()))
+	}
+	sort.Strings(keys)
+	return keys
+}
diff --git a/ethdb/leveldb/leveldb_test.go b/ethdb/leveldb/leveldb_test.go
new file mode 100644
index 000000000..421d9b469
--- /dev/null
+++ b/ethdb/leveldb/leveldb_test.go
@@ -0,0 +1,40 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package leveldb
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/ethdb/dbtest"
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+func TestLevelDB(t *testing.T) {
+	t.Run("DatabaseSuite", func(t *testing.T) {
+		dbtest.TestDatabaseSuite(t, func() ethdb.KeyValueStore {
+			db, err := leveldb.Open(storage.NewMemStorage(), nil)
+			if err != nil {
+				t.Fatal(err)
+			}
+			return &Database{
+				db: db,
+			}
+		})
+	})
+}
diff --git a/ethdb/memorydb/memorydb_test.go b/ethdb/memorydb/memorydb_test.go
index 325c065c1..dba18ad30 100644
--- a/ethdb/memorydb/memorydb_test.go
+++ b/ethdb/memorydb/memorydb_test.go
@@ -17,84 +17,16 @@
 package memorydb
 
 import (
-	"bytes"
 	"testing"
-)
-
-// Tests that key-value iteration on top of a memory database works.
-func TestMemoryDBIterator(t *testing.T) {
-	tests := []struct {
-		content map[string]string
-		prefix  string
-		order   []string
-	}{
-		// Empty databases should be iterable
-		{map[string]string{}, "", nil},
-		{map[string]string{}, "non-existent-prefix", nil},
 
-		// Single-item databases should be iterable
-		{map[string]string{"key": "val"}, "", []string{"key"}},
-		{map[string]string{"key": "val"}, "k", []string{"key"}},
-		{map[string]string{"key": "val"}, "l", nil},
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/ethdb/dbtest"
+)
 
-		// Multi-item databases should be fully iterable
-		{
-			map[string]string{"k1": "v1", "k5": "v5", "k2": "v2", "k4": "v4", "k3": "v3"},
-			"",
-			[]string{"k1", "k2", "k3", "k4", "k5"},
-		},
-		{
-			map[string]string{"k1": "v1", "k5": "v5", "k2": "v2", "k4": "v4", "k3": "v3"},
-			"k",
-			[]string{"k1", "k2", "k3", "k4", "k5"},
-		},
-		{
-			map[string]string{"k1": "v1", "k5": "v5", "k2": "v2", "k4": "v4", "k3": "v3"},
-			"l",
-			nil,
-		},
-		// Multi-item databases should be prefix-iterable
-		{
-			map[string]string{
-				"ka1": "va1", "ka5": "va5", "ka2": "va2", "ka4": "va4", "ka3": "va3",
-				"kb1": "vb1", "kb5": "vb5", "kb2": "vb2", "kb4": "vb4", "kb3": "vb3",
-			},
-			"ka",
-			[]string{"ka1", "ka2", "ka3", "ka4", "ka5"},
-		},
-		{
-			map[string]string{
-				"ka1": "va1", "ka5": "va5", "ka2": "va2", "ka4": "va4", "ka3": "va3",
-				"kb1": "vb1", "kb5": "vb5", "kb2": "vb2", "kb4": "vb4", "kb3": "vb3",
-			},
-			"kc",
-			nil,
-		},
-	}
-	for i, tt := range tests {
-		// Create the key-value data store
-		db := New()
-		for key, val := range tt.content {
-			if err := db.Put([]byte(key), []byte(val)); err != nil {
-				t.Fatalf("test %d: failed to insert item %s:%s into database: %v", i, key, val, err)
-			}
-		}
-		// Iterate over the database with the given configs and verify the results
-		it, idx := db.NewIteratorWithPrefix([]byte(tt.prefix)), 0
-		for it.Next() {
-			if !bytes.Equal(it.Key(), []byte(tt.order[idx])) {
-				t.Errorf("test %d: item %d: key mismatch: have %s, want %s", i, idx, string(it.Key()), tt.order[idx])
-			}
-			if !bytes.Equal(it.Value(), []byte(tt.content[tt.order[idx]])) {
-				t.Errorf("test %d: item %d: value mismatch: have %s, want %s", i, idx, string(it.Value()), tt.content[tt.order[idx]])
-			}
-			idx++
-		}
-		if err := it.Error(); err != nil {
-			t.Errorf("test %d: iteration failed: %v", i, err)
-		}
-		if idx != len(tt.order) {
-			t.Errorf("test %d: iteration terminated prematurely: have %d, want %d", i, idx, len(tt.order))
-		}
-	}
+func TestMemoryDB(t *testing.T) {
+	t.Run("DatabaseSuite", func(t *testing.T) {
+		dbtest.TestDatabaseSuite(t, func() ethdb.KeyValueStore {
+			return New()
+		})
+	})
 }