sharding: tests pass, services updated to include shardDB

Former-commit-id: 8b8b695ddc0a39bfe6a536fd7b7f40d74c4105da [formerly 829d481af0eebd1647a34006018761e3e64c5e3e]
Former-commit-id: 1d607fcb8fae1327c346bdf3557ec40a8816a09b

sharding/database/database_test.go

@@ -0,0 +1,92 @@
+package database
+
+import (
+	"strconv"
+	"testing"
+)
+
+var db ShardBackend
+
+func init() {
+	shardDB, err := NewShardDB("/tmp/datadir", "shardchaindata")
+	if err != nil {
+		panic(err)
+	}
+	db = shardDB
+}
+
+// Testing the concurrency of the shardDB with multiple processes attempting to write.
+func Test_DBConcurrent(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		go func(val string) {
+			if err := db.Put([]byte("ralph merkle"), []byte(val)); err != nil {
+				t.Errorf("could not save value in db: %v", err)
+			}
+		}(strconv.Itoa(i))
+	}
+}
+
+func Test_DBPut(t *testing.T) {
+	if err := db.Put([]byte("ralph merkle"), []byte{1, 2, 3}); err != nil {
+		t.Errorf("could not save value in db: %v", err)
+	}
+}
+
+func Test_DBHas(t *testing.T) {
+	key := []byte("ralph merkle")
+
+	if err := db.Put(key, []byte{1, 2, 3}); err != nil {
+		t.Fatalf("could not save value in db: %v", err)
+	}
+
+	has, err := db.Has(key)
+	if err != nil {
+		t.Errorf("could not check if db has key: %v", err)
+	}
+	if !has {
+		t.Errorf("db should have key: %v", key)
+	}
+
+	key2 := []byte{}
+	has2, err := db.Has(key2)
+	if err != nil {
+		t.Errorf("could not check if db has key: %v", err)
+	}
+	if has2 {
+		t.Errorf("db should not have non-existent key: %v", key2)
+	}
+}
+
+func Test_DBGet(t *testing.T) {
+	key := []byte("ralph merkle")
+
+	if err := db.Put(key, []byte{1, 2, 3}); err != nil {
+		t.Fatalf("could not save value in db: %v", err)
+	}
+
+	val, err := db.Get(key)
+	if err != nil {
+		t.Errorf("get failed: %v", err)
+	}
+	if len(val) == 0 {
+		t.Errorf("no value stored for key")
+	}
+
+	key2 := []byte{}
+	val2, err := db.Get(key2)
+	if len(val2) != 0 {
+		t.Errorf("non-existent key should not have a value. key=%v, value=%v", key2, val2)
+	}
+}
+
+func Test_DBDelete(t *testing.T) {
+	key := []byte("ralph merkle")
+
+	if err := db.Put(key, []byte{1, 2, 3}); err != nil {
+		t.Fatalf("could not save value in db: %v", err)
+	}
+
+	if err := db.Delete(key); err != nil {
+		t.Errorf("could not delete key: %v", key)
+	}
+}