feat: add region repartition group procedure infrastructure (#7299)

* feat: add region repartition group procedure infrastructure

Signed-off-by: WenyXu <wenymedia@gmail.com>

* chore: apply suggestions from CR

Signed-off-by: WenyXu <wenymedia@gmail.com>

---------

Signed-off-by: WenyXu <wenymedia@gmail.com>

src/common/meta/src/kv_backend.rs

@@ -34,6 +34,8 @@ pub mod memory;
 #[cfg(any(feature = "mysql_kvbackend", feature = "pg_kvbackend"))]
 pub mod rds;
 pub mod test;
+#[cfg(any(test, feature = "testing"))]
+pub mod test_util;
 pub mod txn;
 pub mod util;
 pub type KvBackendRef<E = Error> = Arc<dyn KvBackend<Error = E> + Send + Sync>;

src/common/meta/src/kv_backend/test_util.rs

@@ -0,0 +1,125 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::any::Any;
+use std::sync::Arc;
+
+use derive_builder::Builder;
+
+use crate::error::Result;
+use crate::kv_backend::txn::{Txn, TxnResponse};
+use crate::kv_backend::{
+    BatchDeleteRequest, BatchDeleteResponse, BatchGetRequest, BatchGetResponse, BatchPutRequest,
+    BatchPutResponse, DeleteRangeRequest, DeleteRangeResponse, KvBackend, PutRequest, PutResponse,
+    RangeRequest, RangeResponse, TxnService,
+};
+
+pub type MockFn<Req, Resp> = Arc<dyn Fn(Req) -> Result<Resp> + Send + Sync>;
+
+/// A mock kv backend for testing.
+#[derive(Builder)]
+pub struct MockKvBackend {
+    #[builder(setter(strip_option), default)]
+    pub range_fn: Option<MockFn<RangeRequest, RangeResponse>>,
+    #[builder(setter(strip_option), default)]
+    pub put_fn: Option<MockFn<PutRequest, PutResponse>>,
+    #[builder(setter(strip_option), default)]
+    pub batch_put_fn: Option<MockFn<BatchPutRequest, BatchPutResponse>>,
+    #[builder(setter(strip_option), default)]
+    pub batch_get_fn: Option<MockFn<BatchGetRequest, BatchGetResponse>>,
+    #[builder(setter(strip_option), default)]
+    pub delete_range_fn: Option<MockFn<DeleteRangeRequest, DeleteRangeResponse>>,
+    #[builder(setter(strip_option), default)]
+    pub batch_delete_fn: Option<MockFn<BatchDeleteRequest, BatchDeleteResponse>>,
+    #[builder(setter(strip_option), default)]
+    pub txn: Option<MockFn<Txn, TxnResponse>>,
+    #[builder(setter(strip_option), default)]
+    pub max_txn_ops: Option<usize>,
+}
+
+#[async_trait::async_trait]
+impl TxnService for MockKvBackend {
+    type Error = crate::error::Error;
+
+    async fn txn(&self, txn: Txn) -> Result<TxnResponse> {
+        if let Some(f) = &self.txn {
+            f(txn)
+        } else {
+            unimplemented!()
+        }
+    }
+
+    fn max_txn_ops(&self) -> usize {
+        self.max_txn_ops.unwrap()
+    }
+}
+
+#[async_trait::async_trait]
+impl KvBackend for MockKvBackend {
+    fn name(&self) -> &str {
+        "mock_kv_backend"
+    }
+
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    async fn range(&self, req: RangeRequest) -> Result<RangeResponse> {
+        if let Some(f) = &self.range_fn {
+            f(req)
+        } else {
+            unimplemented!()
+        }
+    }
+
+    async fn put(&self, req: PutRequest) -> Result<PutResponse> {
+        if let Some(f) = &self.put_fn {
+            f(req)
+        } else {
+            unimplemented!()
+        }
+    }
+
+    async fn batch_put(&self, req: BatchPutRequest) -> Result<BatchPutResponse> {
+        if let Some(f) = &self.batch_put_fn {
+            f(req)
+        } else {
+            unimplemented!()
+        }
+    }
+
+    async fn batch_get(&self, req: BatchGetRequest) -> Result<BatchGetResponse> {
+        if let Some(f) = &self.batch_get_fn {
+            f(req)
+        } else {
+            unimplemented!()
+        }
+    }
+
+    async fn delete_range(&self, req: DeleteRangeRequest) -> Result<DeleteRangeResponse> {
+        if let Some(f) = &self.delete_range_fn {
+            f(req)
+        } else {
+            unimplemented!()
+        }
+    }
+
+    async fn batch_delete(&self, req: BatchDeleteRequest) -> Result<BatchDeleteResponse> {
+        if let Some(f) = &self.batch_delete_fn {
+            f(req)
+        } else {
+            unimplemented!()
+        }
+    }
+}