diff --git a/.flake8 b/.flake8
index b8f0639..b1142f5 100644
--- a/.flake8
+++ b/.flake8
@@ -1,6 +1,5 @@
 [flake8]
 ignore = E402
-exclude = marimapper/backends/fadecandy/opc.py, venv, marimapper/database.py, marimapper/read_write_model.py
+exclude = marimapper/backends/fadecandy/opc.py, venv, marimapper/pycolmap_tools/*
 max-line-length=127
-max-complexity = 10
-extend-ignore = W503, E203, C901
\ No newline at end of file
+extend-ignore = W503, E203
\ No newline at end of file
diff --git a/marimapper/backends/fcmega/fcmega_backend.py b/marimapper/backends/fcmega/fcmega_backend.py
index 68694a8..8320499 100644
--- a/marimapper/backends/fcmega/fcmega_backend.py
+++ b/marimapper/backends/fcmega/fcmega_backend.py
@@ -10,12 +10,9 @@ def __init__(self):
         self.fc_mega = FCMega()
         self.leds = [(0, 0, 0) for _ in range(self.get_led_count())]
         self.running = True
-        self.update_thread = threading.Thread(target=self._run)
+        self.update_thread = threading.Thread(target=self._run, daemon=True)
         self.update_thread.start()
 
-    def __del__(self):
-        self.running = False
-
     def get_led_count(self):
         return 24 * 400
 
diff --git a/marimapper/camera.py b/marimapper/camera.py
index 8180e5c..338c3f9 100644
--- a/marimapper/camera.py
+++ b/marimapper/camera.py
@@ -36,7 +36,7 @@ def __init__(self, device_id):
                 break
 
         if not self.device.isOpened():
-            logging.error(f"Failed to connect to camera {device_id}")
+            raise RuntimeError(f"Failed to connect to camera {device_id}")
 
         self.set_resolution(self.get_width(), self.get_height())  # Don't ask
 
@@ -71,7 +71,8 @@ def set_resolution(self, width, height):
         new_width = self.get_width()
         new_height = self.get_height()
 
-        if width != new_width or height != new_height:
+        # this is cov ignored as it's a strange position to be in but ultimately fine
+        if width != new_width or height != new_height:  # pragma: no cover
             logging.error(
                 f"Failed to set camera {self.device_id} resolution to {width} x {height}",
             )
diff --git a/marimapper/database_populator.py b/marimapper/database_populator.py
index b0360b7..ef068f5 100644
--- a/marimapper/database_populator.py
+++ b/marimapper/database_populator.py
@@ -3,7 +3,7 @@
 
 import numpy as np
 
-from marimapper.database import COLMAPDatabase
+from marimapper.pycolmap_tools.database import COLMAPDatabase
 
 
 def populate(db_path, led_maps_2d):
diff --git a/marimapper/led_map_3d.py b/marimapper/led_map_3d.py
index ec8ef86..b860428 100644
--- a/marimapper/led_map_3d.py
+++ b/marimapper/led_map_3d.py
@@ -13,13 +13,13 @@ def __init__(self, data=None):
         if data is not None:
             self.data = data
 
-    def __setitem__(self, led_index, led_data):
+    def __setitem__(self, led_index, led_data):  # pragma: no cover
         self.data[led_index] = led_data
 
-    def __getitem__(self, led_index):
+    def __getitem__(self, led_index):  # pragma: no cover
         return self.data[led_index]
 
-    def __contains__(self, led_index):
+    def __contains__(self, led_index):  # pragma: no cover
         return led_index in self.data
 
     def __len__(self):
@@ -64,9 +64,6 @@ def rescale(self, target_inter_distance=1.0):
         for cam in self.cameras:
             cam[1] *= scale
 
-    def get_normal_list(self):
-        return np.array([self[led_id]["normal"] for led_id in self.keys()])
-
     def get_inter_led_distance(self):
         max_led_id = max(self.keys())
 
diff --git a/marimapper/map_cleaner.py b/marimapper/map_cleaner.py
index dbfda93..71217c2 100644
--- a/marimapper/map_cleaner.py
+++ b/marimapper/map_cleaner.py
@@ -72,44 +72,3 @@ def fill_gaps(led_map, max_dist_err=0.2, max_missing=5):
             total_leds_filled += leds_missing
 
     return total_leds_filled
-
-
-def extract_strips(led_map, max_dist_err=0.5):
-
-    max_led_id = max(led_map.keys())
-
-    strips = [[]]
-    led_id = -1
-
-    led_to_led_distance = find_inter_led_distance(led_map)
-
-    max_dist = (1 + max_dist_err) * led_to_led_distance
-    min_dist = (1 - max_dist_err) * led_to_led_distance
-
-    while True:
-
-        led_id += 1
-
-        if led_id > max_led_id:
-            break
-
-        if led_id not in led_map:
-            continue
-
-        if led_id + 1 not in led_map:
-            if strips[-1]:
-                strips[-1].append(led_id)
-                strips.append([])
-            continue
-
-        distance = _distance_between_leds(led_map[led_id], led_map[led_id + 1])
-
-        if not (min_dist < distance < max_dist):
-            if strips[-1]:
-                strips[-1].append(led_id)
-                strips.append([])
-            continue
-
-        strips[-1].append(led_id)
-
-    return strips
diff --git a/marimapper/model.py b/marimapper/model.py
index 69ddfcc..d735505 100644
--- a/marimapper/model.py
+++ b/marimapper/model.py
@@ -2,7 +2,7 @@
 
 import numpy as np
 
-from marimapper.read_write_model import (
+from marimapper.pycolmap_tools.read_write_model import (
     qvec2rotmat,
     read_images_binary,
     read_points3D_binary,
diff --git a/marimapper/pycolmap_tools/__init__.py b/marimapper/pycolmap_tools/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/marimapper/database.py b/marimapper/pycolmap_tools/database.py
similarity index 99%
rename from marimapper/database.py
rename to marimapper/pycolmap_tools/database.py
index 1e15a6d..1b12781 100644
--- a/marimapper/database.py
+++ b/marimapper/pycolmap_tools/database.py
@@ -1,4 +1,3 @@
-# fmt: off
 # Copyright (c) 2023, ETH Zurich and UNC Chapel Hill.
 # All rights reserved.
 #
@@ -429,5 +428,3 @@ def example_usage():
 
 if __name__ == "__main__":
     example_usage()
-
-# fmt: on
diff --git a/marimapper/read_write_model.py b/marimapper/pycolmap_tools/read_write_model.py
similarity index 99%
rename from marimapper/read_write_model.py
rename to marimapper/pycolmap_tools/read_write_model.py
index eec9b08..037feb2 100644
--- a/marimapper/read_write_model.py
+++ b/marimapper/pycolmap_tools/read_write_model.py
@@ -1,4 +1,3 @@
-# fmt: off
 # Copyright (c) 2023, ETH Zurich and UNC Chapel Hill.
 # All rights reserved.
 #
@@ -604,4 +603,3 @@ def main():
 
 if __name__ == "__main__":
     main()
-# fmt: on
diff --git a/marimapper/utils.py b/marimapper/utils.py
index 1051139..8f87592 100644
--- a/marimapper/utils.py
+++ b/marimapper/utils.py
@@ -61,7 +61,7 @@ def add_backend_args(parser):
     parser.add_argument("--server", type=str, help="Some backends require a server")
 
 
-def get_user_confirmation(prompt):
+def get_user_confirmation(prompt):  # pragma: no coverage
 
     try:
         uin = input(logging.colorise(prompt, logging.Col.BLUE))
@@ -86,13 +86,21 @@ def load_custom_backend(backend_file, server=None):
 
     backend = custom_backend.Backend(server) if server else custom_backend.Backend()
 
-    if "get_led_count" not in dir(backend):
-        raise RuntimeError("Your backend does not have a get_led_count function")
+    check_backend(backend)
 
-    if "set_led" not in dir(backend):
-        raise RuntimeError("Your backend does not have a set_led function")
+    return backend
+
+
+def check_backend(backend):
 
-    if len(signature(backend.get_led_count).parameters) != 0:
+    missing_funcs = {"get_led_count", "set_led"}.difference(set(dir(backend)))
+
+    if missing_funcs:
+        raise RuntimeError(
+            f"Your backend does not have the following functions: {missing_funcs}"
+        )
+
+    if len(signature(backend.get_led_count).parameters) != 0:  # pragma: no coverage
         raise RuntimeError(
             "Your backend get_led_count function should not take any arguments"
         )
@@ -102,8 +110,6 @@ def load_custom_backend(backend_file, server=None):
             "Your backend set_led function should only take two arguments"
         )
 
-    return backend
-
 
 def get_backend(backend_name, server=""):
     if backend_name == "fadecandy":
diff --git a/marimapper/visualize_model.py b/marimapper/visualize_model.py
index a6fb19f..d555b88 100644
--- a/marimapper/visualize_model.py
+++ b/marimapper/visualize_model.py
@@ -101,7 +101,7 @@ def reload_geometry__(self, first=False):
             np.array([led_map.data[led_id]["pos"] for led_id in led_map.keys()])
         )
         self.point_cloud.normals = open3d.utility.Vector3dVector(
-            led_map.get_normal_list() * 0.2
+            np.array([led_map[led_id]["normal"] for led_id in led_map.keys()]) * 0.2
         )
 
         self.strip_set.points = self.point_cloud.points
diff --git a/pyproject.toml b/pyproject.toml
index e0fa11f..7242f51 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,10 +35,11 @@ readme = "README.md"
 license = {file = "LICENSE"}
 
 
-
 [project.optional-dependencies]
 develop = [
     "pytest",
+    "pytest-cov",
+    "pytest-mock",
     "black",
     "flake8",
     "flake8-bugbear"
@@ -62,5 +63,14 @@ omit = [
     "*/__main__.py",
     "marimapper/backends/*",
     "marimapper/scripts/*",
-    "marimapper/read_write_model.py"
-    ]
\ No newline at end of file
+    "marimapper/pycolmap_tools/*"
+    ]
+
+[tool.black]
+exclude = '''
+(/(
+    | venv
+    | marimapper/backends
+    | marimapper/pycolmap_tools
+)/)
+'''
\ No newline at end of file
diff --git a/test/test_backend.py b/test/test_backend.py
new file mode 100644
index 0000000..3209f37
--- /dev/null
+++ b/test/test_backend.py
@@ -0,0 +1,167 @@
+import pytest
+import tempfile
+
+from marimapper.utils import get_backend
+
+
+def test_basic_usage():
+
+    temp_backend_file = tempfile.NamedTemporaryFile(delete=False, suffix=".py")
+    temp_backend_file.write(
+        b"""
+class Backend:
+
+    def __init__(self):
+        pass
+
+    def get_led_count(self):
+        return 1
+
+    def set_led(self, led_index, on):
+        pass
+"""
+    )
+    temp_backend_file.close()
+    backend = get_backend(temp_backend_file.name)
+
+    assert backend.get_led_count() == 1
+
+
+def test_invalid_backend_due_to_missing_function():
+    temp_backend_file = tempfile.NamedTemporaryFile(delete=False, suffix=".py")
+    temp_backend_file.write(
+        b"""
+class Backend:
+
+        def __init__(self):
+            pass
+
+        def get_leds(self): # Should be get_led_count()
+            return 1
+
+        def set_led(self, led_index, on):
+            pass
+    """
+    )
+    temp_backend_file.close()
+
+    with pytest.raises(RuntimeError):
+        get_backend(temp_backend_file.name)
+
+
+def test_invalid_backend_due_to_missing_function_arguments():
+    temp_backend_file = tempfile.NamedTemporaryFile(delete=False, suffix=".py")
+    temp_backend_file.write(
+        b"""
+class Backend:
+
+        def __init__(self):
+            pass
+
+        def get_led_count(self) -> int:
+            return 1
+
+        def set_led(self, led_index): # this is missing the on parameter
+            pass
+    """
+    )
+    temp_backend_file.close()
+
+    with pytest.raises(RuntimeError):
+        get_backend(temp_backend_file.name)
+
+
+def test_fadecandy(monkeypatch):
+
+    from marimapper.backends.fadecandy import opc
+
+    def get_client_patch(uri):
+        class ClientPatch:
+            def put_pixels(self, _):
+                pass
+
+        return ClientPatch()
+
+    monkeypatch.setattr(opc, "Client", get_client_patch)
+
+    get_backend("fadecandy")
+    get_backend("fadecandy", "1.2.3.4")
+
+
+def test_wled(monkeypatch):
+
+    import requests
+
+    def return_response_patch(*arg, **kwargs):
+        class ResponsePatch:
+            status_code = 200
+
+            def json(self):
+                return {"leds": {"count": 1}}
+
+        return ResponsePatch()
+
+    monkeypatch.setattr(requests, "post", return_response_patch)
+    monkeypatch.setattr(requests, "get", return_response_patch)
+
+    get_backend("wled")
+    get_backend("wled", "1.2.3.4")
+
+
+def test_fcmega(monkeypatch):
+
+    import serial
+    import serial.tools.list_ports
+
+    class SerialPatch:
+
+        def __init__(self, _):
+            self.is_open = True
+
+        def write(self, _):
+            pass
+
+        def read(self, _):
+            return b"1"
+
+    def comports_patch():
+        class ComportPatch:
+            serial_number = "FCM000"
+            name = "10"
+
+        return [ComportPatch()]
+
+    monkeypatch.setattr(serial, "Serial", SerialPatch)
+    monkeypatch.setattr(serial.tools.list_ports, "comports", comports_patch)
+
+    get_backend("fcmega")
+
+
+def test_pixelblaze(monkeypatch):
+
+    # mini_racer uses import pkg_resources which is depreciated
+    with pytest.warns(DeprecationWarning):
+
+        import pixelblaze
+
+        class PixelblazePatch:
+            def __init__(self, _):
+                pass
+
+            def setActivePatternByName(self, _):
+                pass
+
+            def getPixelCount(self):
+                return 1
+
+        monkeypatch.setattr(pixelblaze, "Pixelblaze", PixelblazePatch)
+
+        get_backend("pixelblaze", "1.2.3.4")
+
+
+def test_invalid_or_none_backend():
+
+    assert get_backend("None") is None
+
+    with pytest.raises(RuntimeError):
+        get_backend("invalid_backend")
diff --git a/test/test_camera.py b/test/test_camera.py
new file mode 100644
index 0000000..f60cf74
--- /dev/null
+++ b/test/test_camera.py
@@ -0,0 +1,21 @@
+import pytest
+from marimapper.camera import Camera
+
+
+def test_valid_device():
+
+    cam = Camera("test/MariMapper-Test-Data/9_point_box/cam_0/capture_0000.png")
+
+    image = cam.read()
+
+    assert image.shape == (480, 640)  # Grey
+
+    image_bw = cam.read(color=True)
+
+    assert image_bw.shape == (480, 640, 4)  # RGBA
+
+
+def test_invalid_device():
+
+    with pytest.raises(RuntimeError):
+        Camera(device_id="bananas")
diff --git a/test/test_custom_backend.py b/test/test_custom_backend.py
deleted file mode 100644
index fee53f7..0000000
--- a/test/test_custom_backend.py
+++ /dev/null
@@ -1,49 +0,0 @@
-import pytest
-import tempfile
-
-from marimapper.utils import load_custom_backend
-
-
-def test_basic_usage():
-
-    temp_backend_file = tempfile.NamedTemporaryFile(delete=False, suffix=".py")
-    temp_backend_file.write(
-        b"""
-class Backend:
-
-    def __init__(self):
-        pass
-
-    def get_led_count(self) -> int:
-        return 1
-
-    def set_led(self, led_index: int, on: bool) -> None:
-        pass
-"""
-    )
-    temp_backend_file.close()
-    backend = load_custom_backend(temp_backend_file.name)
-
-    assert backend.get_led_count() == 1
-
-
-def test_invalid_backend():
-    temp_backend_file = tempfile.NamedTemporaryFile(delete=False, suffix=".py")
-    temp_backend_file.write(
-        b"""
-class Backend:
-
-        def __init__(self):
-            pass
-
-        def get_leds(self) -> int: # Should be get_led_count()
-            return 1
-
-        def set_led(self, led_index: int, on: bool) -> None:
-            pass
-    """
-    )
-    temp_backend_file.close()
-
-    with pytest.raises(RuntimeError):
-        load_custom_backend(temp_backend_file.name)
diff --git a/test/test_reconstruction.py b/test/test_reconstruction.py
index c8de6dc..0598f0a 100644
--- a/test/test_reconstruction.py
+++ b/test/test_reconstruction.py
@@ -1,4 +1,5 @@
 import numpy as np
+import pytest
 
 from marimapper.sfm import SFM
 from marimapper.led_map_2d import get_all_2d_led_maps
@@ -87,3 +88,34 @@ def test_reconstruct_higbeam():
     map_3d = SFM.process__(highbeam_map)
 
     assert map_3d is not None
+
+
+# this test does a re-scale, but should keep the dimensions about the same
+def test_rescale():
+    maps = get_all_2d_led_maps("test/scan")
+
+    map_3d = SFM.process__(maps, rescale=True)
+
+    assert map_3d.get_inter_led_distance() == pytest.approx(1.0)
+
+
+def test_connected():
+
+    maps = get_all_2d_led_maps("test/scan")
+
+    map_3d = SFM.process__(maps)
+
+    assert len(map_3d) == 21
+
+    connected = map_3d.get_connected_leds()
+    assert (6, 7) not in connected
+    assert (13, 14) not in connected
+
+
+def test_interpolate():
+
+    maps = get_all_2d_led_maps("test/scan")
+
+    map_3d = SFM.process__(maps, interpolate=True)
+
+    assert len(map_3d) == 23