diff --git a/mypy/build.py b/mypy/build.py
index 682fa1e00398..3a5fb6b66542 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -42,6 +42,7 @@
 from mypy.stats import dump_type_stats
 from mypy.types import Type
 from mypy.version import __version__
+from mypy.defaults import ALLOW_FIXTURES
 
 
 # We need to know the location of this file to load data, but
@@ -143,8 +144,9 @@ def build(sources: List[BuildSource],
         # debug).  This is a test-only feature, so assume our files are laid out
         # as in the source tree.
         root_dir = dirname(dirname(__file__))
-        lib_path.insert(0, os.path.join(root_dir, 'test-data', 'unit', 'lib-stub'))
-    else:
+        if ALLOW_FIXTURES:
+            lib_path.insert(0, os.path.join(root_dir, 'test-data', 'unit', 'lib-stub'))
+    if not options.use_builtins_fixtures or not ALLOW_FIXTURES:
         for source in sources:
             if source.path:
                 # Include directory of the program file in the module search path.
diff --git a/mypy/defaults.py b/mypy/defaults.py
index b5398f990d11..d6707925ff8c 100644
--- a/mypy/defaults.py
+++ b/mypy/defaults.py
@@ -2,3 +2,5 @@
 PYTHON3_VERSION = (3, 6)
 CACHE_DIR = '.mypy_cache'
 CONFIG_FILE = 'mypy.ini'
+# Set this to False (here in the file, not dynamically!) to disable builtins fixtures in tests
+ALLOW_FIXTURES = True
diff --git a/mypy/test/data.py b/mypy/test/data.py
index a0573d55479c..0885af3ca2f1 100644
--- a/mypy/test/data.py
+++ b/mypy/test/data.py
@@ -12,6 +12,8 @@
 
 from mypy.myunit import TestCase, SkipTestCaseException
 
+from mypy.defaults import ALLOW_FIXTURES
+
 
 def parse_test_cases(
         path: str,
@@ -63,7 +65,8 @@ def parse_test_cases(
                     assert arg is not None
                     file_entry = (join(base_path, arg), '\n'.join(p[i].data))
                     if p[i].id == 'file':
-                        files.append(file_entry)
+                        if arg != 'builtins.py' or ALLOW_FIXTURES:
+                            files.append(file_entry)
                     elif p[i].id == 'outfile':
                         output_files.append(file_entry)
                 elif p[i].id in ('builtins', 'builtins_py2'):
@@ -77,7 +80,8 @@ def parse_test_cases(
                         # Python 2
                         fnam = '__builtin__.pyi'
                     with open(mpath) as f:
-                        files.append((join(base_path, fnam), f.read()))
+                        if ALLOW_FIXTURES:
+                            files.append((join(base_path, fnam), f.read()))
                 elif p[i].id == 'stale':
                     arg = p[i].arg
                     if arg is None: