Add through relationships tests

Author: ken-kost

test/through_relationships_test.exs

@@ -0,0 +1,302 @@
+# SPDX-FileCopyrightText: 2019 ash_postgres contributors <https://github.com/ash-project/ash_postgres/graphs.contributors>
+#
+# SPDX-License-Identifier: MIT
+
+defmodule AshPostgres.Test.ThroughRelationshipsTest do
+  use AshPostgres.RepoCase, async: false
+
+  require Ash.Query
+
+  setup do
+    school_1 = create_school("School One")
+    school_2 = create_school("School Two")
+
+    classroom_1 = create_classroom("Math 101", school_1.id)
+    classroom_2 = create_classroom("Science 101", school_1.id)
+    classroom_3 = create_classroom("History 101", school_2.id)
+
+    teacher_1 = create_teacher("Mr. Smith")
+    teacher_2 = create_teacher("Ms. Johnson")
+    teacher_3 = create_teacher("Dr. Williams")
+    teacher_4 = create_teacher("Prof. Adams")
+
+    student_1 = create_student("Alice", classroom_1.id)
+    student_2 = create_student("Bob", classroom_2.id)
+
+    %{
+      school_1: school_1,
+      school_2: school_2,
+      classroom_1: classroom_1,
+      classroom_2: classroom_2,
+      classroom_3: classroom_3,
+      teacher_1: teacher_1,
+      teacher_2: teacher_2,
+      teacher_3: teacher_3,
+      teacher_4: teacher_4,
+      student_1: student_1,
+      student_2: student_2
+    }
+  end
+
+  describe "has_many through relationships" do
+    test "loads teachers through classrooms -> classroom_teachers -> teacher", setup do
+      %{school_1: school_1, classroom_1: classroom_1, classroom_2: classroom_2} = setup
+      %{teacher_1: teacher_1, teacher_2: teacher_2, teacher_3: teacher_3} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_1.id, teacher_2.id)
+      assign_teacher(classroom_2.id, teacher_2.id)
+      assign_teacher(classroom_2.id, teacher_3.id)
+
+      school_with_teachers = Ash.load!(school_1, :teachers)
+
+      teacher_names =
+        school_with_teachers.teachers
+        |> Enum.map(& &1.name)
+        |> Enum.sort()
+
+      assert teacher_names == ["Dr. Williams", "Mr. Smith", "Ms. Johnson"]
+    end
+
+    test "has_many through with no results", setup do
+      %{school_2: school_2} = setup
+
+      school_with_teachers = Ash.load!(school_2, :teachers)
+      assert school_with_teachers.teachers == []
+    end
+
+    test "has_many through with empty intermediate results", setup do
+      %{school_1: school_1} = setup
+
+      school_with_teachers = Ash.load!(school_1, :teachers)
+      assert school_with_teachers.teachers == []
+    end
+
+    test "3-hop path: school -> classrooms -> classroom_teachers -> teacher", setup do
+      %{school_1: school_1, classroom_1: classroom_1} = setup
+      %{teacher_1: teacher_1} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+
+      school_with_teachers = Ash.load!(school_1, :teachers)
+
+      assert length(school_with_teachers.teachers) == 1
+      assert hd(school_with_teachers.teachers).name == "Mr. Smith"
+    end
+  end
+
+  describe "many_to_many through atom list" do
+    test "retired_teachers loads only teachers with retired_at set", setup do
+      %{classroom_1: classroom_1} = setup
+      %{teacher_1: teacher_1, teacher_2: teacher_2} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_1.id, teacher_2.id)
+
+      classroom_with_retired = Ash.load!(classroom_1, :retired_teachers)
+
+      assert length(classroom_with_retired.retired_teachers) == 1
+      assert hd(classroom_with_retired.retired_teachers).name == teacher_1.name
+    end
+
+    test "retired_teachers returns empty when no teachers are retired", setup do
+      %{classroom_1: classroom_1} = setup
+      %{teacher_1: teacher_1} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+
+      classroom_with_retired = Ash.load!(classroom_1, :retired_teachers)
+      assert classroom_with_retired.retired_teachers == []
+    end
+
+    test "teacher many_to_many classrooms via atom list through", setup do
+      %{classroom_1: classroom_1, classroom_2: classroom_2} = setup
+      %{teacher_1: teacher_1} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_2.id, teacher_1.id)
+
+      teacher_with_classrooms = Ash.load!(teacher_1, :classrooms)
+
+      classroom_names =
+        teacher_with_classrooms.classrooms
+        |> Enum.map(& &1.name)
+        |> Enum.sort()
+
+      assert classroom_names == ["Math 101", "Science 101"]
+    end
+  end
+
+  describe "has_one through relationships" do
+    test "active_teacher loads the non-retired teacher", setup do
+      %{classroom_1: classroom_1} = setup
+      %{teacher_1: teacher_1, teacher_2: teacher_2} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_1.id, teacher_2.id)
+
+      classroom_loaded = Ash.load!(classroom_1, :active_teacher)
+      assert classroom_loaded.active_teacher.name == teacher_2.name
+    end
+
+    test "student teacher through classroom active_teacher", setup do
+      %{classroom_1: classroom_1} = setup
+      %{teacher_1: teacher_1, teacher_2: teacher_2} = setup
+      %{student_1: student_1} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_1.id, teacher_2.id)
+
+      student_with_teacher = Ash.load!(student_1, :teacher)
+      assert student_with_teacher.teacher.name == teacher_2.name
+    end
+  end
+
+  describe "aggregates on through relationships" do
+    test "school teacher_count counts all teachers through path", setup do
+      %{school_1: school_1, classroom_1: classroom_1, classroom_2: classroom_2} = setup
+      %{teacher_1: teacher_1, teacher_2: teacher_2} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_2.id, teacher_1.id)
+      assign_teacher(classroom_2.id, teacher_2.id)
+
+      school_with_agg =
+        AshPostgres.Test.Through.School
+        |> Ash.Query.filter(id == ^school_1.id)
+        |> Ash.Query.load([:classroom_count, :teacher_count, :teacher_count_via_path])
+        |> Ash.read_one!()
+
+      assert school_with_agg.classroom_count == 2
+      assert school_with_agg.teacher_count == 3
+      assert school_with_agg.teacher_count_via_path == 3
+    end
+
+    test "school retired_teacher_count counts only retired", setup do
+      %{school_1: school_1, classroom_1: classroom_1} = setup
+      %{teacher_1: teacher_1, teacher_2: teacher_2, teacher_3: teacher_3} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_1.id, teacher_2.id)
+
+      school_with_agg =
+        AshPostgres.Test.Through.School
+        |> Ash.Query.filter(id == ^school_1.id)
+        |> Ash.Query.load(:retired_teacher_count)
+        |> Ash.Query.load(:active_teacher_count)
+        |> Ash.read_one!()
+
+      assert school_with_agg.retired_teacher_count == 1
+      assert school_with_agg.active_teacher_count == 1
+
+      assign_teacher(classroom_1.id, teacher_3.id)
+
+      school_with_agg =
+        AshPostgres.Test.Through.School
+        |> Ash.Query.filter(id == ^school_1.id)
+        |> Ash.Query.load(:retired_teacher_count)
+        |> Ash.Query.load(:active_teacher_count)
+        |> Ash.read_one!()
+
+      assert school_with_agg.retired_teacher_count == 2
+      assert school_with_agg.active_teacher_count == 1
+    end
+
+    test "multiple schools with aggregates", setup do
+      %{school_1: school_1, school_2: school_2} = setup
+      %{classroom_1: classroom_1, classroom_2: classroom_2, classroom_3: classroom_3} = setup
+
+      %{teacher_1: teacher_1, teacher_2: teacher_2, teacher_3: teacher_3, teacher_4: teacher_4} =
+        setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_1.id, teacher_2.id)
+      assign_teacher(classroom_2.id, teacher_3.id)
+      assign_teacher(classroom_3.id, teacher_2.id)
+      assign_teacher(classroom_3.id, teacher_3.id)
+      assign_teacher(classroom_3.id, teacher_4.id)
+
+      [school_one, school_two] =
+        AshPostgres.Test.Through.School
+        |> Ash.Query.load([:classroom_count, :teacher_count, :teacher_count_via_path])
+        |> Ash.Query.filter(id in [^school_1.id, ^school_2.id])
+        |> Ash.Query.sort(:name)
+        |> Ash.read!()
+
+      assert school_one.name == "School One"
+      assert school_one.classroom_count == 2
+      assert school_one.teacher_count == 3
+      assert school_one.teacher_count_via_path == 3
+
+      assert school_two.name == "School Two"
+      assert school_two.classroom_count == 1
+      assert school_two.teacher_count == 3
+      assert school_two.teacher_count_via_path == 3
+    end
+
+    test "students know their active teacher", setup do
+      %{school_1: school_1, classroom_1: classroom_1, classroom_2: classroom_2} = setup
+
+      %{teacher_1: teacher_1, teacher_2: teacher_2, teacher_3: teacher_3, teacher_4: teacher_4} =
+        setup
+
+      %{student_1: student_1, student_2: student_2} = setup
+
+      assign_teacher(classroom_1.id, teacher_1.id)
+      assign_teacher(classroom_2.id, teacher_2.id)
+
+      student_1 = Ash.load!(student_1, [:teacher, :retired_teacher_count])
+      student_2 = Ash.load!(student_2, [:teacher, :retired_teacher_count])
+
+      assign_teacher(classroom_1.id, teacher_3.id)
+      assign_teacher(classroom_2.id, teacher_4.id)
+
+      student_1 = Ash.load!(student_1, [:teacher, :retired_teacher_count])
+      student_2 = Ash.load!(student_2, [:teacher, :retired_teacher_count])
+
+      assert student_1.teacher.name == teacher_3.name
+      assert student_1.retired_teacher_count == 1
+      assert student_2.teacher.name == teacher_4.name
+      assert student_2.retired_teacher_count == 1
+
+      school_1 = Ash.load!(school_1, [:retired_teacher_count, :active_teacher_count])
+
+      assert school_1.retired_teacher_count == 2
+      assert school_1.active_teacher_count == 2
+    end
+  end
+
+  defp create_school(name) do
+    AshPostgres.Test.Through.School
+    |> Ash.Changeset.for_create(:create, %{name: name})
+    |> Ash.create!()
+  end
+
+  defp create_classroom(name, school_id) do
+    AshPostgres.Test.Through.Classroom
+    |> Ash.Changeset.for_create(:create, %{name: name, school_id: school_id})
+    |> Ash.create!()
+  end
+
+  defp create_teacher(name) do
+    AshPostgres.Test.Through.Teacher
+    |> Ash.Changeset.for_create(:create, %{name: name})
+    |> Ash.create!()
+  end
+
+  defp create_student(name, classroom_id) do
+    AshPostgres.Test.Through.Student
+    |> Ash.Changeset.for_create(:create, %{name: name, classroom_id: classroom_id})
+    |> Ash.create!()
+  end
+
+  defp assign_teacher(classroom_id, teacher_id, opts \\ []) do
+    attrs =
+      %{classroom_id: classroom_id, teacher_id: teacher_id}
+      |> Map.merge(Map.new(opts))
+
+    AshPostgres.Test.Through.ClassroomTeacher
+    |> Ash.Changeset.for_create(:assign, attrs)
+    |> Ash.create!()
+  end
+end