diff --git a/lib/galaxy_test/base/mock_http_server.py b/lib/galaxy_test/base/mock_http_server.py
index a0ae2a7576f..4d9899ffa5b 100644
--- a/lib/galaxy_test/base/mock_http_server.py
+++ b/lib/galaxy_test/base/mock_http_server.py
@@ -171,7 +171,12 @@ class MockHttpServer:
         path = f"/mock/{self._counter}/{filename}" if filename else f"/mock/{self._counter}"
 
         if file_path is not None:
-            encoded_body = Path(file_path).read_bytes()
+            file_path_obj = Path(file_path)
+            if not file_path_obj.is_absolute():
+                # Resolve relative paths from the Galaxy project root
+                galaxy_root = Path(__file__).resolve().parents[3]
+                file_path_obj = galaxy_root / file_path_obj
+            encoded_body = file_path_obj.read_bytes()
         elif isinstance(body, str):
             encoded_body = body.encode()
         else:
diff --git a/packages/app/setup.cfg b/packages/app/setup.cfg
index 7e2b39ca457..8b5be408e75 100644
--- a/packages/app/setup.cfg
+++ b/packages/app/setup.cfg
@@ -85,6 +85,7 @@ python_requires = >=3.10
 
 [options.extras_require]
 test =
+    galaxy-test-base
     mock-ssh-server
     pkce
     pykwalify
diff --git a/packages/files/setup.cfg b/packages/files/setup.cfg
index 6cfdcff63ac..885a5d2e38c 100644
--- a/packages/files/setup.cfg
+++ b/packages/files/setup.cfg
@@ -42,6 +42,7 @@ python_requires = >=3.10
 
 [options.extras_require]
 test =
+    galaxy-test-base
     pytest
     gcsfs
     s3fs>=2023.1.0
diff --git a/packages/packages_by_dep_dag.txt b/packages/packages_by_dep_dag.txt
index f592240bbcb..c7b058853a2 100644
--- a/packages/packages_by_dep_dag.txt
+++ b/packages/packages_by_dep_dag.txt
@@ -2,7 +2,6 @@ tool_util_models
 util
 
 config
-files
 job_metrics
 navigation
 objectstore
@@ -10,10 +9,13 @@ schema
 tool_shed_schema
 tool_util
 
+test_base
+
+files
+
 data
 selenium
 tours
-test_base
 
 auth
 job_execution