refactor: reorganize tests into admin and vendor subdirectories

Split integration tests into logical admin/ and vendor/ subdirectories
for better organization. Updated fixture imports and test structure.

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

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

tests/integration/api/v1/admin/test_vendors.py

@@ -0,0 +1,116 @@
+# tests/integration/api/v1/admin/test_vendors.py
+"""Integration tests for admin vendor management endpoints.
+
+Tests the /api/v1/admin/vendors/* endpoints.
+"""
+import pytest
+
+
+@pytest.mark.integration
+@pytest.mark.api
+@pytest.mark.admin
+class TestAdminVendorsAPI:
+    """Test admin vendor management endpoints at /api/v1/admin/vendors/*."""
+
+    def test_get_all_vendors_admin(self, client, admin_headers, test_vendor):
+        """Test admin getting all vendors."""
+        response = client.get("/api/v1/admin/vendors", headers=admin_headers)
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["total"] >= 1
+        assert len(data["vendors"]) >= 1
+
+        # Check that test_vendor is in the response
+        vendor_codes = [
+            vendor["vendor_code"]
+            for vendor in data["vendors"]
+            if "vendor_code" in vendor
+        ]
+        assert test_vendor.vendor_code in vendor_codes
+
+    def test_get_all_vendors_non_admin(self, client, auth_headers):
+        """Test non-admin trying to access admin vendor endpoint."""
+        response = client.get("/api/v1/admin/vendors", headers=auth_headers)
+
+        assert response.status_code == 403
+        data = response.json()
+        assert data["error_code"] == "ADMIN_REQUIRED"
+
+    def test_toggle_vendor_verification_admin(self, client, admin_headers, test_vendor):
+        """Test admin setting vendor verification status."""
+        response = client.put(
+            f"/api/v1/admin/vendors/{test_vendor.id}/verification",
+            headers=admin_headers,
+            json={"is_verified": True},
+        )
+
+        assert response.status_code == 200
+        data = response.json()
+        assert "id" in data
+        assert "vendor_code" in data
+        assert "is_verified" in data
+
+    def test_toggle_vendor_verification_not_found(self, client, admin_headers):
+        """Test admin verifying non-existent vendor."""
+        response = client.put(
+            "/api/v1/admin/vendors/99999/verification",
+            headers=admin_headers,
+            json={"is_verified": True},
+        )
+
+        assert response.status_code == 404
+        data = response.json()
+        assert data["error_code"] == "VENDOR_NOT_FOUND"
+        assert "99999" in data["message"]
+        assert "not found" in data["message"]
+
+    def test_toggle_vendor_status_admin(self, client, admin_headers, test_vendor):
+        """Test admin setting vendor active status."""
+        response = client.put(
+            f"/api/v1/admin/vendors/{test_vendor.id}/status",
+            headers=admin_headers,
+            json={"is_active": False},
+        )
+
+        assert response.status_code == 200
+        data = response.json()
+        assert "id" in data
+        assert "vendor_code" in data
+        assert "is_active" in data
+
+    def test_toggle_vendor_status_not_found(self, client, admin_headers):
+        """Test admin toggling status for non-existent vendor."""
+        response = client.put(
+            "/api/v1/admin/vendors/99999/status",
+            headers=admin_headers,
+            json={"is_active": True},
+        )
+
+        assert response.status_code == 404
+        data = response.json()
+        assert data["error_code"] == "VENDOR_NOT_FOUND"
+
+    def test_get_vendor_statistics(self, client, admin_headers):
+        """Test admin getting vendor statistics."""
+        response = client.get("/api/v1/admin/vendors/stats", headers=admin_headers)
+
+        assert response.status_code == 200
+        data = response.json()
+        assert "total" in data
+        assert "verified" in data
+        assert "pending" in data
+        assert "inactive" in data
+        assert isinstance(data["total"], int)
+
+    def test_admin_pagination_vendors(self, client, admin_headers, test_vendor):
+        """Test vendor pagination works correctly."""
+        response = client.get(
+            "/api/v1/admin/vendors?skip=0&limit=1", headers=admin_headers
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert data["total"] >= 1
+        assert len(data["vendors"]) >= 0
+        assert "skip" in data
+        assert "limit" in data