Add comprehensive tests for Monitoring.Check schema

Tests cover:
- Valid and invalid changesets
- All required field validations
- Foreign key constraints
- Status enum values
- Schema field types and associations
- Binary ID usage for primary/foreign keys

All 16 tests passing with good coverage of schema validation logic.

test/towerops/monitoring/check_test.exs

@@ -0,0 +1,209 @@
+defmodule Towerops.Monitoring.CheckTest do
+  use Towerops.DataCase, async: true
+
+  import Towerops.AccountsFixtures
+
+  alias Towerops.Monitoring.Check
+
+  describe "changeset/2" do
+    setup do
+      user = user_fixture()
+      {:ok, organization} = Towerops.Organizations.create_organization(%{name: "Test Org"}, user.id)
+
+      {:ok, site} =
+        Towerops.Sites.create_site(%{
+          name: "Test Site",
+          organization_id: organization.id
+        })
+
+      {:ok, device} =
+        Towerops.Devices.create_device(%{
+          name: "Test Device",
+          ip_address: "192.168.1.1",
+          site_id: site.id
+        })
+
+      {:ok, device: device}
+    end
+
+    test "valid changeset with all fields", %{device: device} do
+      attrs = %{
+        device_id: device.id,
+        status: :success,
+        response_time_ms: 12.5,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+
+      assert changeset.valid?
+      assert get_change(changeset, :device_id) == device.id
+      assert get_change(changeset, :status) == :success
+      assert get_change(changeset, :response_time_ms) == 12.5
+      assert get_change(changeset, :checked_at)
+    end
+
+    test "valid changeset with failure status", %{device: device} do
+      attrs = %{
+        device_id: device.id,
+        status: :failure,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+
+      assert changeset.valid?
+      assert get_change(changeset, :status) == :failure
+      # response_time_ms is optional and can be nil for failures
+      refute Map.has_key?(changeset.changes, :response_time_ms)
+    end
+
+    test "requires device_id" do
+      attrs = %{
+        status: :success,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+
+      refute changeset.valid?
+      assert "can't be blank" in errors_on(changeset).device_id
+    end
+
+    test "requires status" do
+      attrs = %{
+        device_id: Ecto.UUID.generate(),
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+
+      refute changeset.valid?
+      assert "can't be blank" in errors_on(changeset).status
+    end
+
+    test "requires checked_at" do
+      attrs = %{
+        device_id: Ecto.UUID.generate(),
+        status: :success
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+
+      refute changeset.valid?
+      assert "can't be blank" in errors_on(changeset).checked_at
+    end
+
+    test "accepts only valid status values", %{device: device} do
+      # Invalid status value
+      attrs = %{
+        device_id: device.id,
+        status: :invalid_status,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+
+      refute changeset.valid?
+      assert "is invalid" in errors_on(changeset).status
+    end
+
+    test "validates foreign key constraint on insert", %{device: device} do
+      # This test requires actual database insert
+      valid_attrs = %{
+        device_id: device.id,
+        status: :success,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, valid_attrs)
+      assert {:ok, _check} = Repo.insert(changeset)
+
+      # Now try with invalid device_id
+      invalid_attrs = %{
+        device_id: Ecto.UUID.generate(),
+        status: :success,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, invalid_attrs)
+      assert {:error, changeset} = Repo.insert(changeset)
+      assert "does not exist" in errors_on(changeset).device_id
+    end
+
+    test "response_time_ms can be nil", %{device: device} do
+      attrs = %{
+        device_id: device.id,
+        status: :failure,
+        response_time_ms: nil,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+      assert changeset.valid?
+    end
+
+    test "response_time_ms accepts float values", %{device: device} do
+      attrs = %{
+        device_id: device.id,
+        status: :success,
+        response_time_ms: 123.456,
+        checked_at: DateTime.utc_now()
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+      assert changeset.valid?
+      assert get_change(changeset, :response_time_ms) == 123.456
+    end
+
+    test "checked_at accepts DateTime", %{device: device} do
+      now = DateTime.utc_now()
+
+      attrs = %{
+        device_id: device.id,
+        status: :success,
+        checked_at: now
+      }
+
+      changeset = Check.changeset(%Check{}, attrs)
+      assert changeset.valid?
+    end
+  end
+
+  describe "schema" do
+    test "has correct fields" do
+      fields = Check.__schema__(:fields)
+      assert :id in fields
+      assert :device_id in fields
+      assert :status in fields
+      assert :response_time_ms in fields
+      assert :checked_at in fields
+      assert :inserted_at in fields
+    end
+
+    test "belongs to device" do
+      assocs = Check.__schema__(:associations)
+      assert :device in assocs
+
+      assoc = Check.__schema__(:association, :device)
+      assert assoc.queryable == Towerops.Devices.Device
+    end
+
+    test "uses binary_id for primary key" do
+      assert Check.__schema__(:type, :id) == :binary_id
+    end
+
+    test "uses binary_id for foreign keys" do
+      assert Check.__schema__(:type, :device_id) == :binary_id
+    end
+
+    test "status is an enum" do
+      assert {:parameterized, {Ecto.Enum, _}} = Check.__schema__(:type, :status)
+    end
+
+    test "does not have updated_at timestamp" do
+      fields = Check.__schema__(:fields)
+      refute :updated_at in fields
+    end
+  end
+end