Removing single column limit from join table M2M mapping detection. (#1593)

test/Feature/QuerySpec.hs

@@ -351,6 +351,21 @@ spec actualPgVersion = do
         [json|[{"id":1,"tasks":[{"id":1},{"id":2},{"id":3},{"id":4}]},{"id":2,"tasks":[{"id":5},{"id":6},{"id":7}]},{"id":3,"tasks":[{"id":1},{"id":5}]}]|]
         { matchHeaders = [matchContentTypeJson] }
 
+    it "requesting many<->many relation using composite key" $
+      get "/files?filename=eq.autoexec.bat&project_id=eq.1&select=filename,users_tasks(user_id,task_id)" `shouldRespondWith`
+        [json|[{"filename":"autoexec.bat","users_tasks":[{"user_id":1,"task_id":1},{"user_id":3,"task_id":1}]}]|]
+        { matchHeaders = [matchContentTypeJson] }
+
+    it "requesting data using many<->many relation defined by composite keys" $
+      get "/users_tasks?user_id=eq.1&task_id=eq.1&select=user_id,files(filename,content)" `shouldRespondWith`
+        [json|[{"user_id":1,"files":[{"filename":"command.com","content":"#include <unix.h>"},{"filename":"autoexec.bat","content":"@ECHO OFF"},{"filename":"README.md","content":"# make $$$!"}]}]|]
+        { matchHeaders = [matchContentTypeJson] }
+
+    it "requesting data using many<->many (composite keys) relation using hint" $
+      get "/users_tasks?user_id=eq.1&task_id=eq.1&select=user_id,files!touched_files(filename,content)" `shouldRespondWith`
+        [json|[{"user_id":1,"files":[{"filename":"command.com","content":"#include <unix.h>"},{"filename":"autoexec.bat","content":"@ECHO OFF"},{"filename":"README.md","content":"# make $$$!"}]}]|]
+        { matchHeaders = [matchContentTypeJson] }
+
     it "requesting children with composite key" $
       get "/users_tasks?user_id=eq.2&task_id=eq.6&select=*, comments(content)" `shouldRespondWith`
         [json|[{"user_id":2,"task_id":6,"comments":[{"content":"Needs to be delivered ASAP"}]}]|]