diff --git a/src/techui_builder/__main__.py b/src/techui_builder/__main__.py
index 586b5a1..2867e1e 100644
--- a/src/techui_builder/__main__.py
+++ b/src/techui_builder/__main__.py
@@ -155,7 +155,7 @@ def main(
     )
 
     gui.setup()
-    gui.generate_screens()
+    gui.create_screens()
 
     logger_.info(f"Screens generated for {gui.conf.beamline.short_dom}.")
 
diff --git a/src/techui_builder/autofill.py b/src/techui_builder/autofill.py
index 6299748..7789e63 100644
--- a/src/techui_builder/autofill.py
+++ b/src/techui_builder/autofill.py
@@ -1,5 +1,6 @@
 import logging
 import os
+from collections import defaultdict
 from dataclasses import dataclass, field
 from pathlib import Path
 
@@ -8,6 +9,7 @@
 
 from techui_builder.builder import Builder, _get_action_group
 from techui_builder.models import Component
+from techui_builder.utils import read_bob
 
 logger_ = logging.getLogger(__name__)
 
@@ -16,41 +18,32 @@
 class Autofiller:
     path: Path
     macros: list[str] = field(default_factory=lambda: ["prefix", "desc", "file"])
+    widgets: dict[str, ObjectifiedElement] = field(
+        default_factory=defaultdict, init=False, repr=False
+    )
 
     def read_bob(self) -> None:
-        # Read the bob file
-        self.tree = objectify.parse(self.path)
-
-        # Find the root tag (in this case: <display version="2.0.0">)
-        self.root = self.tree.getroot()
+        self.tree, self.widgets = read_bob(self.path)
 
     def autofill_bob(self, gui: "Builder"):
         # Get names from component list
 
-        # Loop over objects in the xml
-        # i.e. every tag below <display version="2.0.0">
-        # but not any nested tags below them
-        for child in self.root.iterchildren():
-            # If widget is a symbol (i.e. a component)
-            if child.tag == "widget" and child.get("type", default=None) == "symbol":
-                # Extract it's name
-                symbol_name = child.name
-
-                # If the name exists in the component list
-                if symbol_name in gui.conf.components.keys():
-                    # Get first copy of component (should only be one)
-                    comp = next(
-                        (comp for comp in gui.conf.components if comp == symbol_name),
-                    )
-
-                    self.replace_content(
-                        widget=child,
-                        component_name=comp,
-                        component=gui.conf.components[comp],
-                    )
-
-                    # Add option to allow left mouse click to run action
-                    child["run_actions_on_mouse_click"] = "true"
+        for symbol_name, child in self.widgets.items():
+            # If the name exists in the component list
+            if symbol_name in gui.conf.components.keys():
+                # Get first copy of component (should only be one)
+                comp = next(
+                    (comp for comp in gui.conf.components if comp == symbol_name),
+                )
+
+                self.replace_content(
+                    widget=child,
+                    component_name=comp,
+                    component=gui.conf.components[comp],
+                )
+
+                # Add option to allow left mouse click to run action
+                child["run_actions_on_mouse_click"] = "true"
 
     def write_bob(self, filename: Path):
         # Check if data/ dir exists and if not, make it
diff --git a/src/techui_builder/builder.py b/src/techui_builder/builder.py
index de16cba..e02585b 100644
--- a/src/techui_builder/builder.py
+++ b/src/techui_builder/builder.py
@@ -1,5 +1,6 @@
 import json
 import logging
+import os
 from collections import defaultdict
 from dataclasses import _MISSING_TYPE, dataclass, field
 from pathlib import Path
@@ -11,6 +12,7 @@
 
 from techui_builder.generate import Generator
 from techui_builder.models import Entity, TechUi
+from techui_builder.validator import Validator
 
 logger_ = logging.getLogger(__name__)
 
@@ -57,8 +59,34 @@ def setup(self):
         """Run intial setup, e.g. extracting entries from service ioc.yaml."""
         self._extract_services()
         synoptic_dir = self._write_directory
+
+        self.clean_bobs()
+
         self.generator = Generator(synoptic_dir)
 
+    def clean_bobs(self):
+        exclude = {"index.bob"}
+        bobs = [
+            bob
+            for bob in self._write_directory.glob("*.bob")
+            if bob.name not in exclude
+        ]
+
+        self.validator = Validator(bobs)
+        self.validator.check_bobs()
+
+        # Get bobs that are only present in the bobs list (i.e. generated)
+        self.generated_bobs = list(set(bobs) ^ set(self.validator.validate.values()))
+
+        logger_.info("Preserving edited screens for validation.")
+        logger_.debug(f"Screens to validate: {list(self.validator.validate.keys())}")
+
+        logger_.info("Cleaning synoptic/ of generated screens.")
+        # Remove any generated bobs that exist
+        for bob in self.generated_bobs:
+            logger_.debug(f"Removing generated screen: {bob.name}")
+            os.remove(bob)
+
     def _extract_services(self):
         """
         Finds the services folders in the services directory
@@ -95,13 +123,20 @@ def _extract_entities(self, ioc_yaml: Path):
                     )
                     self.entities[new_entity.P].append(new_entity)
 
-    def _generate_screen(self, screen_name: str, screen_components: list[Entity]):
-        self.generator.load_screen(screen_name, screen_components)
-        self.generator.build_groups()
-        self.generator.write_screen(self._write_directory)
+    def _generate_screen(self, screen_name: str):
+        self.generator.build_screen(screen_name)
+        self.generator.write_screen(screen_name, self._write_directory)
+
+    def _validate_screen(self, screen_name: str):
+        # Get the generated widgets to validate against
+        widgets = self.generator.widgets
+        widget_group = self.generator.group
+        assert widget_group is not None
+        widget_group_name = widget_group.get_element_value("name")
+        self.validator.validate_bob(screen_name, widget_group_name, widgets)
 
-    def generate_screens(self):
-        """Generate the screens for each component in techui.yaml"""
+    def create_screens(self):
+        """Create the screens for each component in techui.yaml"""
         if len(self.entities) == 0:
             logger_.critical("No ioc entities found, has setup() been run?")
             exit()
@@ -124,7 +159,18 @@ def generate_screens(self):
                             continue
                         screen_entities.extend(self.entities[extra_p])
 
-                self._generate_screen(component_name, screen_entities)
+                # This is used by both generate and validate,
+                # so called beforehand for tidyness
+                self.generator.build_widgets(component_name, screen_entities)
+                self.generator.build_groups(component_name)
+
+                screens_to_validate = list(self.validator.validate.keys())
+
+                if component_name in screens_to_validate:
+                    self._validate_screen(component_name)
+                else:
+                    self._generate_screen(component_name)
+
             else:
                 logger_.warning(
                     f"{self.techui.name}: The prefix [bold]{component.prefix}[/bold]\
diff --git a/src/techui_builder/generate.py b/src/techui_builder/generate.py
index bd35396..c812828 100644
--- a/src/techui_builder/generate.py
+++ b/src/techui_builder/generate.py
@@ -20,9 +20,6 @@
 class Generator:
     synoptic_dir: Path = field(repr=False)
 
-    screen_name: str = field(init=False)
-    screen_components: list[Entity] = field(init=False)
-
     # These are global params for the class (not accessible by user)
     support_path: Path = field(init=False, repr=False)
     techui_support: dict = field(init=False, repr=False)
@@ -33,6 +30,7 @@ class Generator:
     widgets: list[ActionButton | EmbeddedDisplay] = field(
         default_factory=list[ActionButton | EmbeddedDisplay], init=False, repr=False
     )
+    group: Group | None = field(default=None, init=False, repr=False)
 
     # Add group padding, and self.widget_x for placing widget in x direction relative to
     # other widgets, with a widget count to reset the self.widget_x dimension when the
@@ -55,10 +53,6 @@ def _read_map(self):
         with open(support_yaml) as map:
             self.techui_support = yaml.safe_load(map)
 
-    def load_screen(self, screen_name: str, screen_components: list[Entity]):
-        self.screen_name = screen_name
-        self.screen_components = screen_components
-
     def _get_screen_dimensions(self, file: str) -> tuple[int, int]:
         """
         Parses the bob files for information on the height
@@ -248,7 +242,7 @@ def _allocate_widget(
         return new_widget
 
     def _create_widget(
-        self, component: Entity
+        self, name: str, component: Entity
     ) -> EmbeddedDisplay | ActionButton | None | list[EmbeddedDisplay | ActionButton]:
         # if statement below is check if the suffix is
         # missing from the component description. If
@@ -261,7 +255,7 @@ def _create_widget(
         except KeyError:
             logger_.warning(
                 f"No available widget for {component.type} in screen \
-{self.screen_name}. Skipping..."
+{name}. Skipping..."
             )
             return None
 
@@ -337,21 +331,14 @@ def layout_widgets(self, widgets: list[EmbeddedDisplay | ActionButton]):
 
         return sorted_widgets
 
-    def build_groups(self):
-        """
-        Create a group to fill with widgets
-        """
-        # Create screen
-        self.screen_ = pscreen.Screen(self.screen_name)
+    def build_widgets(self, screen_name: str, screen_components: list[Entity]):
         # Empty widget buffer
         self.widgets = []
 
-        # create widget and group objects
-
         # order is an enumeration of the components, used to list them,
         # and serves as functionality in the math for formatting.
-        for component in self.screen_components:
-            new_widget = self._create_widget(component=component)
+        for component in screen_components:
+            new_widget = self._create_widget(name=screen_name, component=component)
             if new_widget is None:
                 continue
             if isinstance(new_widget, list):
@@ -359,6 +346,11 @@ def build_groups(self):
                 continue
             self.widgets.append(new_widget)
 
+    def build_groups(self, screen_name: str):
+        """
+        Create a group to fill with widgets
+        """
+
         if self.widgets == []:
             # No widgets found, so just back out
             return
@@ -369,28 +361,43 @@ def build_groups(self):
         height, width = self._get_group_dimensions(self.widgets)
 
         self.group = Group(
-            self.screen_name,
+            screen_name,
             0,
             0,
             width,
             height,
         )
 
+        # TODO: we shouldn't need this assert; fix
+        assert self.group is not None
         self.group.version("2.0.0")
         self.group.add_widget(self.widgets)
+
+    def build_screen(self, screen_name):
+        """
+        Build the screen with the widget groups.
+        """
+        # Create screen
+        self.screen_ = pscreen.Screen(screen_name)
+
+        # TODO: I don't like this
+        if self.group is None:
+            # No group found, so just back out
+            return
+
         self.screen_.add_widget(self.group)
 
-    def write_screen(self, directory: Path):
+    def write_screen(self, screen_name: str, directory: Path):
         """Write the screen to file"""
 
         if self.widgets == []:
             logger_.warning(
-                f"Could not write screen: {self.screen_name} \
+                f"Could not write screen: {screen_name} \
 as no widgets were available"
             )
             return
 
         if not directory.exists():
             os.mkdir(directory)
-        self.screen_.write_screen(f"{directory}/{self.screen_name}.bob")
-        logger_.info(f"{self.screen_name}.bob has been created successfully")
+        self.screen_.write_screen(f"{directory}/{screen_name}.bob")
+        logger_.info(f"{screen_name}.bob has been created successfully")
diff --git a/src/techui_builder/utils.py b/src/techui_builder/utils.py
new file mode 100644
index 0000000..11b1304
--- /dev/null
+++ b/src/techui_builder/utils.py
@@ -0,0 +1,32 @@
+from lxml import objectify
+from lxml.objectify import ObjectifiedElement
+
+
+def read_bob(path):
+    # Read the bob file
+    tree = objectify.parse(path)
+
+    # Find the root tag (in this case: <display version="2.0.0">)
+    root = tree.getroot()
+
+    widgets = get_widgets(root)
+
+    return tree, widgets
+
+
+def get_widgets(root: ObjectifiedElement):
+    widgets: dict[str, ObjectifiedElement] = {}
+    # Loop over objects in the xml
+    # i.e. every tag below <display version="2.0.0">
+    # but not any nested tags below them
+    for child in root.iterchildren():
+        # If widget is a symbol (i.e. a component)
+        if child.tag == "widget" and child.get("type", default=None) in [
+            "symbol",
+            "group",
+        ]:
+            name = child.name.text
+            assert name is not None
+            widgets[name] = child
+
+    return widgets
diff --git a/src/techui_builder/validator.py b/src/techui_builder/validator.py
new file mode 100644
index 0000000..5261326
--- /dev/null
+++ b/src/techui_builder/validator.py
@@ -0,0 +1,77 @@
+import logging
+from collections import defaultdict
+from dataclasses import dataclass, field
+from pathlib import Path
+
+from lxml import etree
+from phoebusgen.widget.widgets import ActionButton, EmbeddedDisplay
+
+from techui_builder.utils import read_bob
+
+LOGGER = logging.getLogger(__name__)
+
+
+@dataclass
+class Validator:
+    bobs: list[Path]
+    validate: dict[str, Path] = field(
+        default_factory=defaultdict, init=False, repr=False
+    )
+
+    def check_bobs(self):
+        for bob in self.bobs:
+            self._check_bob(bob)
+
+    def _check_bob(self, bob_path: Path):
+        # etree has to used as objectify ignore comments
+        xml = etree.parse(bob_path)
+        # fetch all the comments at the base of the tree
+        comments = list(xml.getroot().itersiblings(tag=etree.Comment, preceding=True))
+        if len(comments) > 0:
+            # Check if any comments found are the manually saved tag
+            if any(str(comment).startswith("<!--Saved on ") for comment in comments):
+                self.validate[bob_path.name.removesuffix(".bob")] = bob_path
+
+    def _read_bob(self, path: Path):
+        tree, widgets = read_bob(path)
+        return tree.getroot(), widgets
+
+    def validate_bob(
+        self,
+        screen_name: str,
+        widget_group_name: str,
+        pwidgets: list[EmbeddedDisplay | ActionButton],
+    ):
+        path = self.validate[screen_name]
+        _, file_groups = self._read_bob(path)
+
+        if widget_group_name not in file_groups.keys():
+            return
+
+        file_widgets = [
+            file_widget
+            for file_widget in file_groups[widget_group_name].getchildren()
+            if file_widget.tag == "widget"
+        ]
+
+        for pwidget in pwidgets:
+            pwidget_name = pwidget.get_element_value("name")
+            for file_widget in file_widgets:
+                if pwidget_name == file_widget.name:
+                    assert (
+                        int(pwidget.get_element_value("width")) == file_widget.width
+                    ), (
+                        f"{int(pwidget.get_element_value('width'))} \
+!= {file_widget.width}"
+                    )
+                    assert (
+                        int(pwidget.get_element_value("height")) == file_widget.height
+                    ), (
+                        f"{int(pwidget.get_element_value('height'))} \
+!= {file_widget.height}"
+                    )
+                    assert pwidget.get_element_value("file") == file_widget.file, (
+                        f"{pwidget.get_element_value('file')} != {file_widget.file}"
+                    )
+
+        LOGGER.info(f"{screen_name}.bob has been validated successfully")
diff --git a/tests/conftest.py b/tests/conftest.py
index 119c0ab..945dca5 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -5,6 +5,7 @@
 
 from techui_builder.builder import Builder, JsonMap
 from techui_builder.generate import Generator
+from techui_builder.validator import Validator
 
 
 @pytest.fixture
@@ -46,3 +47,11 @@ def generator():
     g = Generator(synoptic_dir)
 
     return g
+
+
+@pytest.fixture
+def validator():
+    test_bobs = [Path("tests/test_files/motor-edited.bob")]
+    v = Validator(test_bobs)
+
+    return v
diff --git a/tests/test_builder.py b/tests/test_builder.py
index d96fdd8..90da27c 100644
--- a/tests/test_builder.py
+++ b/tests/test_builder.py
@@ -108,27 +108,29 @@ def test_gb_extract_entities(builder, index, type, desc, P, M, R):  # noqa: N803
     assert entity.R == R
 
 
-def test_generate_screens(builder_with_setup):
+def test_create_screens(builder_with_setup):
     # We don't want to access Generator in this test
     builder_with_setup._generate_screen = Mock()
-    builder_with_setup.generate_screens()
+    builder_with_setup._validate_screen = Mock()
+    builder_with_setup.create_screens()
 
     builder_with_setup._generate_screen.assert_called()
+    # builder_with_setup._validate_screen.assert_called()
 
 
-def test_generate_screens_no_entities(builder, caplog):
+def test_create_screens_no_entities(builder, caplog):
     builder.entities = []
 
     # We only wan't to capture CRITICAL output in this test
     with caplog.at_level(logging.CRITICAL):
         with pytest.raises(SystemExit):
-            builder.generate_screens()
+            builder.create_screens()
 
     for log_output in caplog.records:
         assert "No ioc entities found, has setup() been run?" in log_output.message
 
 
-def test_generate_screens_extra_p_does_not_exist(builder_with_setup, caplog):
+def test_create_screens_extra_p_does_not_exist(builder_with_setup, caplog):
     # We don't want to actually generate a screen
     builder_with_setup._generate_screen = Mock(side_effect=None)
 
@@ -137,7 +139,7 @@ def test_generate_screens_extra_p_does_not_exist(builder_with_setup, caplog):
 
     # We only want to capture the ERROR output in this test
     with caplog.at_level(logging.ERROR):
-        builder_with_setup.generate_screens()
+        builder_with_setup.create_screens()
 
     for log_output in caplog.records:
         assert "Extra prefix BAD-PV" in log_output.message
diff --git a/tests/test_files/motor-edited.bob b/tests/test_files/motor-edited.bob
new file mode 100644
index 0000000..93e1b4c
--- /dev/null
+++ b/tests/test_files/motor-edited.bob
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--Saved on 1970-01-01 00:00:01 by TESTER-->
+  <display version="2.0.0">
+    <name>motor</name>
+    <widget type="group" version="2.0.0">
+      <name>motor</name>
+      <x>0</x>
+      <y>0</y>
+      <width>255</width>
+      <height>470</height>
+      <widget type="embedded" version="2.0.0">
+        <name>X</name>
+        <width>205</width>
+        <height>120</height>
+        <file>example/t01-services/synoptic/techui-support/bob/pmac/motor_embed.bob</file>
+        <macros>
+          <P>BL01T-MO-MOTOR-01</P>
+          <M>X</M>
+        </macros>
+        <x>0</x>
+        <y>0</y>
+      </widget>
+    </widget>
+  </display>
diff --git a/tests/test_files/motor.bob b/tests/test_files/motor.bob
index 529674f..70d68b7 100644
--- a/tests/test_files/motor.bob
+++ b/tests/test_files/motor.bob
@@ -11,7 +11,7 @@
         <name>X</name>
         <width>205</width>
         <height>120</height>
-        <file>../../../../src/techui-support/bob/pmac/motor_embed.bob</file>
+        <file>example/t01-services/synoptic/techui-support/bob/pmac/motor_embed.bob</file>
         <macros>
           <P>BL01T-MO-MOTOR-01</P>
           <M>X</M>
@@ -23,7 +23,7 @@
         <name>A</name>
         <width>205</width>
         <height>120</height>
-        <file>../../../../src/techui-support/bob/pmac/motor_embed.bob</file>
+        <file>example/t01-services/synoptic/techui-support/bob/pmac/motor_embed.bob</file>
         <macros>
           <P>BL01T-MO-MOTOR-01</P>
           <M>A</M>
@@ -43,7 +43,7 @@
             <macros>
               <P>BL01T-MO-BRICK-01</P>
             </macros>
-            <file>../../../../src/techui-support/bob/pmac/pmacController.bob</file>
+            <file>example/t01-services/synoptic/techui-support/bob/pmac/pmacController.bob</file>
             <target>tab</target>
           </action>
         </actions>
diff --git a/tests/test_files/motor_bad.bob b/tests/test_files/motor_bad.bob
index 34d32fc..145fc6d 100644
--- a/tests/test_files/motor_bad.bob
+++ b/tests/test_files/motor_bad.bob
@@ -9,7 +9,7 @@
         <name>X</name>
         <width>205</width>
         <height>120</height>
-        <file>../../../../src/techui-support/bob/pmac/motor_embed.bob</file>
+        <file>example/t01-services/synoptic/techui-support/bob/pmac/motor_embed.bob</file>
         <macros>
           <P>BL01T-MO-MOTOR-01</P>
           <M>X</M>
@@ -21,7 +21,7 @@
         <name>A</name>
         <width>205</width>
         <height>120</height>
-        <file>../../../../src/techui-support/bob/pmac/motor_embed.bob</file>
+        <file>example/t01-services/synoptic/techui-support/bob/pmac/motor_embed.bob</file>
         <macros>
           <P>BL01T-MO-MOTOR-01</P>
           <M>A</M>
@@ -41,7 +41,7 @@
             <macros>
               <P>BL01T-MO-BRICK-01</P>
             </macros>
-            <file>../../../../src/techui-support/bob/pmac/pmacController.bob</file>
+            <file>example/t01-services/synoptic/techui-support/bob/pmac/pmacController.bob</file>
             <target>tab</target>
           </action>
         </actions>
diff --git a/tests/test_generate.py b/tests/test_generate.py
index 2adae48..9e708c2 100644
--- a/tests/test_generate.py
+++ b/tests/test_generate.py
@@ -24,14 +24,6 @@ def y(self, val: int):
         self._y = val
 
 
-def test_generator_load_screen(generator):
-    entity = Entity(type="test", P="TEST", desc=None, M=None, R=None)
-    generator.load_screen("test", [entity])
-
-    assert generator.screen_name == "test"
-    assert generator.screen_components == [entity]
-
-
 def test_generator_get_screen_dimensions_good(generator):
     test_embedded_screen = "tests/test_files/motor_embed.bob"
     x, y = generator._get_screen_dimensions(test_embedded_screen)
@@ -116,12 +108,12 @@ def test_generator_get_group_dimensions(generator):
 
 def test_generator_create_widget_keyerror(generator, caplog):
     generator._get_screen_dimensions = Mock(return_value=(800, 1280))
-    generator.screen_name = "test"
+    screen_name = "test"
     component = Entity(
         type="key.notavailable", P="BL23B-DI-MOD-02", desc=None, M=None, R="CAM:"
     )
 
-    result = generator._create_widget(component=component)
+    result = generator._create_widget(name=screen_name, component=component)
 
     assert result is None
     assert (
@@ -138,11 +130,11 @@ def test_generator_create_widget_is_list_of_dicts(generator):
             name="X", file="", x=0, y=0, width=205, height=120
         )
     )
-    generator.screen_name = "test"
+    screen_name = "test"
     component = Entity(
         type="ADAravis.aravisCamera", P="BL23B-DI-MOD-02", desc=None, M=None, R="CAM:"
     )
-    widget = generator._create_widget(component=component)
+    widget = generator._create_widget(name=screen_name, component=component)
     for value in widget:
         assert str(value) == str(
             pwidget.EmbeddedDisplay(name="X", file="", x=0, y=0, width=205, height=120)
@@ -151,11 +143,13 @@ def test_generator_create_widget_is_list_of_dicts(generator):
 
 def test_generator_create_widget_embedded(generator):
     generator._get_screen_dimensions = Mock(return_value=(570, 990))
+    screen_name = "test"
     component = Entity(
         type="ADAravis.aravisCamera", P="BL23B-DI-MOD-02", desc=None, M=None, R="CAM:"
     )
 
     widget = generator._create_widget(
+        name=screen_name,
         component=component,
     )
     control_widget = Path("tests/test_files/widget.xml")
@@ -229,11 +223,13 @@ def test_generator_allocate_widget(generator):
 
 def test_generator_create_widget_related(generator):
     generator._get_screen_dimensions = Mock(return_value=(800, 1280))
+    screen_name = "test"
     component = Entity(
         type="pmac.GeoBrick", P="BL23B-MO-BRICK-01", desc=None, M=":M", R=None
     )
 
     widget = generator._create_widget(
+        name=screen_name,
         component=component,
     )
 
@@ -245,11 +241,13 @@ def test_generator_create_widget_related(generator):
 
 def test_generator_create_widget_related_no_suffix(generator):
     generator._get_screen_dimensions = Mock(return_value=(800, 1280))
+    screen_name = "test"
     component = Entity(
         type="pmac.GeoBrick", P="BL23B-MO-BRICK-01", desc=None, M=None, R=None
     )
 
     widget = generator._create_widget(
+        name=screen_name,
         component=component,
     )
 
@@ -298,7 +296,8 @@ def test_generator_layout_widgets(generator, index, x, y):
     assert arranged_widgets[index]._y == y
 
 
-def test_generator_build_groups(generator):
+# TODO: Split up test
+def test_generator_build_screen(generator):
     generator._create_widget = Mock(return_value=Mock())
     generator.layout_widgets = Mock(
         return_value=[
@@ -309,25 +308,27 @@ def test_generator_build_groups(generator):
         ]
     )
     generator._get_group_dimensions = Mock(return_value=(600, 400))
-    generator.screen_name = "test"
-    generator.screen_components = [Mock(), Mock(), Mock()]
+    screen_name = "test"
+    screen_components = [Mock(), Mock(), Mock()]
 
-    generator.build_groups()
+    generator.build_widgets(screen_name, screen_components)
+    generator.build_groups(screen_name)
+    generator.build_screen(screen_name)
     assert objectify.fromstring(str(generator.screen_)).xpath("//widget[@type='group']")
 
 
 def test_generator_write_screen(generator):
-    generator.screen_name = "test"
+    screen_name = "test"
     generator.screen_ = pscreen.Screen("test")
     generator.widgets = [Mock(), Mock()]
-    generator.write_screen(Path("tests/test_files/"))
+    generator.write_screen(screen_name, Path("tests/test_files/"))
     assert Path("tests/test_files/test.bob").exists()
     Path("tests/test_files/test.bob").unlink()
 
 
 def test_generator_write_screen_no_widgets(generator, caplog):
-    generator.screen_name = "test"
+    screen_name = "test"
     generator.screen_ = pscreen.Screen("test")
     generator.widgets = []
-    generator.write_screen(Path("tests/test_files/"))
+    generator.write_screen(screen_name, Path("tests/test_files/"))
     assert "Could not write screen: test as no widgets were available" in caplog.text
diff --git a/tests/test_validator.py b/tests/test_validator.py
new file mode 100644
index 0000000..0ee4da1
--- /dev/null
+++ b/tests/test_validator.py
@@ -0,0 +1,69 @@
+from pathlib import Path
+from unittest.mock import Mock, patch
+
+from lxml.etree import Element, SubElement, _ElementTree, tostring
+from lxml.objectify import fromstring
+from phoebusgen.widget import EmbeddedDisplay
+
+
+def test_validator_check_bobs(validator):
+    validator._check_bob = Mock()
+
+    validator.check_bobs()
+
+    validator._check_bob.assert_called()
+
+
+def test_validator_check_bob(validator):
+    validator._check_bob(validator.bobs[0])
+
+    assert len(validator.validate.keys()) > 0
+    assert list(validator.validate.keys())[0] == "motor-edited"
+
+
+def test_validator_read_bob(validator):
+    with patch("techui_builder.validator.read_bob") as mock_read_bob:
+        # We need to set the spec of the first Mock so it knows
+        # it has a getroot() function
+        mock_read_bob.return_value = (Mock(spec=_ElementTree), Mock())
+
+        validator._read_bob(validator.bobs[0])
+
+
+# TODO: Clean up this test... (make fixture for mock xml?)
+def test_validator_validate_bob(validator):
+    # You cannot set a text tag of an ObjectifiedElement,
+    # so we need to make an etree.Element and convert it ...
+    mock_root_element = Element("root")
+    mock_widget_element = SubElement(mock_root_element, "widget")
+    mock_name_element = SubElement(mock_widget_element, "name")
+    mock_name_element.text = "motor"
+    mock_width_element = SubElement(mock_widget_element, "width")
+    mock_width_element.text = "205"
+    mock_height_element = SubElement(mock_widget_element, "height")
+    mock_height_element.text = "120"
+    mock_file_element = SubElement(mock_widget_element, "file")
+    mock_file_element.text = (
+        "example/t01-services/synoptic/techui_supportbob/pmac/motor_embed.bob"
+    )
+    # ... which requires this horror
+    mock_element = fromstring(tostring(mock_root_element))
+    # mock_element = ObjectifiedElement(mock_widget_element)
+    # mock_name_element.text = "motor"
+    validator._read_bob = Mock(
+        return_value=(
+            Mock(),
+            {"motor": (mock_element)},
+        )
+    )
+    validator.validate = {"motor-edited": Path("tests/test_files/motor-edited.bob")}
+    test_pwidget = EmbeddedDisplay(
+        "motor",
+        "example/t01-services/synoptic/techui_supportbob/pmac/motor_embed.bob",
+        0,
+        0,
+        205,
+        120,
+    )
+
+    validator.validate_bob("motor-edited", "motor", [test_pwidget])