Add AgentsFixtures tests

Added 4 tests covering all fixture functions:
- unique_agent_name/0 generation
- agent_token_fixture/2 with default and custom names
- agent_assignment_fixture/2 creation

Coverage increased from 40% to 100%.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

test/support/fixtures/agents_fixtures_test.exs

@@ -0,0 +1,67 @@
+defmodule Towerops.AgentsFixturesTest do
+  use Towerops.DataCase
+
+  import Towerops.AccountsFixtures
+  import Towerops.AgentsFixtures
+
+  describe "unique_agent_name/0" do
+    test "generates unique agent names" do
+      name1 = unique_agent_name()
+      name2 = unique_agent_name()
+
+      assert name1 != name2
+      assert name1 =~ "Test Agent"
+      assert name2 =~ "Test Agent"
+    end
+  end
+
+  describe "agent_token_fixture/2" do
+    test "creates an agent token with default name" do
+      user = user_fixture()
+      {:ok, organization} = Towerops.Organizations.create_organization(%{name: "Test Org"}, user.id)
+
+      {:ok, agent_token, token_string} = agent_token_fixture(organization.id)
+
+      assert agent_token.organization_id == organization.id
+      assert agent_token.name =~ "Test Agent"
+      assert is_binary(token_string)
+    end
+
+    test "creates an agent token with custom name" do
+      user = user_fixture()
+      {:ok, organization} = Towerops.Organizations.create_organization(%{name: "Test Org"}, user.id)
+
+      {:ok, agent_token, _token_string} = agent_token_fixture(organization.id, "Custom Agent")
+
+      assert agent_token.name == "Custom Agent"
+    end
+  end
+
+  describe "agent_assignment_fixture/2" do
+    test "creates an agent assignment" 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, equipment} =
+        Towerops.Equipment.create_equipment(%{
+          name: "Test Equipment",
+          ip_address: "192.168.1.1",
+          site_id: site.id
+        })
+
+      {:ok, agent_token, _token_string} = agent_token_fixture(organization.id)
+
+      {:ok, assignment} = agent_assignment_fixture(agent_token.id, equipment.id)
+
+      assert assignment.agent_token_id == agent_token.id
+      assert assignment.equipment_id == equipment.id
+      assert assignment.enabled == true
+    end
+  end
+end