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.

ethdb/memorydb/memorydb_test.go

@@ -17,84 +17,16 @@
 package memorydb
 
 import (
-	"bytes"
 	"testing"
+
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/ethdb/dbtest"
 )
 
-// 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},
-
-		// 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()
+		})
+	})
 }