diff --git a/ratapi/controls.py b/ratapi/controls.py
index 06c457b..9dd815b 100644
--- a/ratapi/controls.py
+++ b/ratapi/controls.py
@@ -206,7 +206,7 @@ def __str__(self) -> str:
     def initialise_IPC(self):
         """Set up the inter-process communication file."""
         IPC_obj, self._IPCFilePath = tempfile.mkstemp()
-        os.write(IPC_obj, b"0")
+        os.write(IPC_obj, b"\x00")
         os.close(IPC_obj)
         return None
 
@@ -221,7 +221,7 @@ def sendStopEvent(self):
         """
         if os.path.isfile(self._IPCFilePath):
             with open(self._IPCFilePath, "wb") as f:
-                f.write(b"1")
+                f.write(b"\x01")
         else:
             warnings.warn("An IPC file was not initialised.", UserWarning, stacklevel=2)
         return None
@@ -230,6 +230,7 @@ def delete_IPC(self):
         """Delete the inter-process communication file."""
         with contextlib.suppress(FileNotFoundError):
             os.remove(self._IPCFilePath)
+        self._IPCFilePath = ""
         return None
 
     def save(self, filepath: str | Path = "./controls.json"):
diff --git a/ratapi/utils/convert.py b/ratapi/utils/convert.py
index 4e2649a..b957789 100644
--- a/ratapi/utils/convert.py
+++ b/ratapi/utils/convert.py
@@ -291,7 +291,14 @@ def fix_invalid_constraints(name: str, constrs: tuple[float, float], value: floa
         if Path(custom_filepath).suffix != ".m":
             custom_filepath += ".m"
         model_name = Path(custom_filepath).stem
-        custom_file = ClassList([CustomFile(name=model_name, filename=custom_filepath, language=Languages.Matlab)])
+        # Assume the custom file is in the same directory as the mat file
+        custom_file = ClassList(
+            [
+                CustomFile(
+                    name=model_name, filename=custom_filepath, language=Languages.Matlab, path=Path(filename).parent
+                )
+            ]
+        )
         layers = ClassList()
         for contrast in contrasts:
             contrast.model = [model_name]
diff --git a/ratapi/utils/plotting.py b/ratapi/utils/plotting.py
index 9293a1a..d4a81e1 100644
--- a/ratapi/utils/plotting.py
+++ b/ratapi/utils/plotting.py
@@ -492,6 +492,8 @@ def update_plot(self, data):
         """
         if self.figure is not None:
             self.figure.clf()
+
+        self.figure.tight_layout()
         plot_ref_sld_helper(
             data,
             self.figure,
@@ -502,7 +504,6 @@ def update_plot(self, data):
             show_legend=self.show_legend,
             animated=True,
         )
-        self.figure.tight_layout(pad=1)
         self.figure.canvas.draw()
         self.bg = self.figure.canvas.copy_from_bbox(self.figure.bbox)
         for line in self.figure.axes[0].lines:
diff --git a/tests/conftest.py b/tests/conftest.py
index 4d5ecc0..bd35919 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -6858,7 +6858,11 @@ def r1_monolayer():
         ),
         custom_files=ratapi.ClassList(
             ratapi.models.CustomFile(
-                name="Model_IIb", filename="Model_IIb.m", function_name="Model_IIb", language="matlab"
+                name="Model_IIb",
+                filename="Model_IIb.m",
+                function_name="Model_IIb",
+                language="matlab",
+                path=Path(__file__).parent / "test_data",
             )
         ),
     )
diff --git a/tests/test_controls.py b/tests/test_controls.py
index ec8cb12..5a83bcc 100644
--- a/tests/test_controls.py
+++ b/tests/test_controls.py
@@ -891,7 +891,7 @@ def test_initialise_IPC() -> None:
     assert test_controls._IPCFilePath != ""
     with open(test_controls._IPCFilePath, "rb") as f:
         file_content = f.read()
-    assert file_content == b"0"
+    assert file_content == b"\x00"
     os.remove(test_controls._IPCFilePath)
 
 
@@ -900,7 +900,7 @@ def test_sendStopEvent(IPC_controls) -> None:
     IPC_controls.sendStopEvent()
     with open(IPC_controls._IPCFilePath, "rb") as f:
         file_content = f.read()
-    assert file_content == b"1"
+    assert file_content == b"\x01"
 
 
 def test_sendStopEvent_empty_file() -> None:
diff --git a/tests/test_convert.py b/tests/test_convert.py
index 2973834..fc6f440 100644
--- a/tests/test_convert.py
+++ b/tests/test_convert.py
@@ -93,7 +93,7 @@ def mock_load(ignored_filename, **ignored_settings):
 
     monkeypatch.setattr("ratapi.utils.convert.loadmat", mock_load, raising=True)
 
-    converted_project = r1_to_project(project)
+    converted_project = r1_to_project(pathlib.Path(__file__).parent / "test_data" / project)
 
     for class_list in ratapi.project.class_lists:
         assert getattr(converted_project, class_list) == getattr(original_project, class_list)