add unit test case

src/graph/executor/algo/FindPathExecutor.cpp

@@ -35,7 +35,7 @@ void FindPathExecutor::init() {
   }
 }
 
-void FindPathExecutor::setNextStepVidFromPath(Interims& paths, const string& var) {
+void FindPathExecutor::setNextStepVid(Interims& paths, const string& var) {
   DataSet Ds;
   for (const auto& path : paths) {
     Row row;
@@ -174,10 +174,8 @@ folly::Future<Status> FindPathExecutor::execute() {
     conjunctPath(leftPaths, rightPaths, ds);
   }
 
-  auto leftVidVar = path->leftVidVar();
-  auto rightVidVar = path->rightVidVar();
-  setNextStepVidFromPath(leftPaths, leftVidVar);
-  setNextStepVidFromPath(rightPaths, rightVidVar);
+  setNextStepVid(leftPaths, path->leftVidVar());
+  setNextStepVid(rightPaths, path->rightVidVar());
   // update history
   preLeftPaths_.swap(leftPaths);
   preRightPaths_.swap(rightPaths);

src/graph/executor/algo/FindPathExecutor.h

@@ -1,15 +1,39 @@
-/* Copyright (c) 2022 vesoft inc. All rights reserved.
- *
- * This source code is licensed under Apache 2.0 License.
- */
+// Copyright (c) 2022 vesoft inc. All rights reserved.
+//
+// This source code is licensed under Apache 2.0 License.
 
 #ifndef GRAPH_EXECUTOR_ALGO_FIND_PATH_EXECUTOR_H_
 #define GRAPH_EXECUTOR_ALGO_FIND_PATH_EXECUTOR_H_
 
 #include "graph/executor/Executor.h"
-// 1、keep path
-// 2 extract dst
-// 3 conjunct path
+
+// FindPath has two inputs.  GetNeighbors(From) & GetNeighbors(To)
+// There are two Main functions
+// First : Get the next vid for GetNeighbors to expand
+// Second: Delete previously visited edges and save the result(iter) to the variable `resultVar`
+//
+// Member:
+// `preLeftPaths_` : is hash table
+//    KEY   : the VID of the visited destination Vertex
+//    VALUE : the number of steps to visit the KEY (starting vertex is 0)
+// since each vertex will only be visited once, if it is a one-way edge expansion, there will be no
+// duplicate edges. we only need to focus on the case of two-way expansion
+//
+// How to delete edges:
+//  determine whether a loop is formed by the number of steps. If the destination vid has been
+//  visited, and the number of steps of the destination vid differs by 2 from the current steps, it
+//  is judged that a loop is formed, the edge needs to be deleted
+//
+// For example: Topology is below
+// a->c, a->b, b->a, b->c
+// statement: get subgraph from 'a' both edge yield vertices as nodes, edges as relationships
+// first steps :  a->b, a->c, a<-b, all edges need to save
+// second steps:  b->a, b<-a, b->c, c<-a
+// since it is a two-way expansion, the negative edge has already been visited,
+// so b<-a & c<-a are deleted
+// b->a : the number of steps of the destination vid `a` is 0, and the current steps is 2. it can be
+// determined that a loop is formed, so this edge also needs to be deleted.
+// b->c : determined by the number of steps that no loop is formed, so keep it
 namespace nebula {
 namespace graph {
 class FindPathExecutor final : public Executor {
@@ -24,7 +48,7 @@ class FindPathExecutor final : public Executor {
  private:
   void init();
   bool conjunctPath(Interims& leftPaths, Interims& rightPaths, DataSet& ds);
-  void setNextStepVidFromPath(Interims& paths, const std::string& var);
+  void setNextStepVid(Interims& paths, const std::string& var);
   void buildPath(Iterator* iter, Interims& currentPath, bool reverse);
 
  private:

src/graph/executor/test/CMakeLists.txt

@@ -97,10 +97,7 @@ nebula_add_test(
         TopNTest.cpp
         AggregateTest.cpp
         JoinTest.cpp
-        BFSShortestTest.cpp
-        ConjunctPathTest.cpp
-        ProduceSemiShortestPathTest.cpp
-        ProduceAllPathsTest.cpp
+        FindPathTest.cpp
         CartesianProductTest.cpp
         AssignTest.cpp
         ShowQueriesTest.cpp

src/graph/executor/test/ConjunctPathTest.cpp

@@ -1,18 +1,18 @@
-/* Copyright (c) 2020 vesoft inc. All rights reserved.
- *
- * This source code is licensed under Apache 2.0 License.
- */
+// Copyright (c) 2022 vesoft inc. All rights reserved.
+//
+// This source code is licensed under Apache 2.0 License.
+//
 
 #include <gtest/gtest.h>
 
 #include "graph/context/QueryContext.h"
-#include "graph/executor/algo/ConjunctPathExecutor.h"
+#include "graph/executor/algo/FindPathExecutor.h"
 #include "graph/planner/plan/Algo.h"
 #include "graph/planner/plan/Logic.h"
 
 namespace nebula {
 namespace graph {
-class ConjunctPathTest : public testing::Test {
+class FindPathTest : public testing::Test {
  protected:
   Path createPath(const std::string& src, const std::vector<std::string>& steps, int type) {
     Path path;