diff --git a/.github/workflows/pull-request.yaml b/.github/workflows/pull-request.yaml
index 2da67ab..cad0dbf 100644
--- a/.github/workflows/pull-request.yaml
+++ b/.github/workflows/pull-request.yaml
@@ -40,7 +40,7 @@ jobs:
       - name: Install dependencies and run tests
         run: |
           uv pip install -e ".[all]" --system
-          uv pip install pytest pytest-cov pytest-xdist --system
+          uv pip install -r requirements/test.txt --system
           make test-cov
       - name: Install and run mypy
         run: |
diff --git a/requirements/test.txt b/requirements/test.txt
new file mode 100644
index 0000000..8b5374e
--- /dev/null
+++ b/requirements/test.txt
@@ -0,0 +1,7 @@
+anyio
+pytest
+pytest-asyncio
+pytest-cov
+pytest-tornasync
+pytest-trio
+pytest-xdist
\ No newline at end of file
diff --git a/sksmithy/_static/tui.tcss b/sksmithy/_static/tui.tcss
index 5ed90ce..4e38a73 100644
--- a/sksmithy/_static/tui.tcss
+++ b/sksmithy/_static/tui.tcss
@@ -12,6 +12,7 @@
 
 Screen {
     align: center middle;
+    min-width: 100vw;
 }
 
 Header {
diff --git a/sksmithy/tui/_components.py b/sksmithy/tui/_components.py
index e93ae99..93f497a 100644
--- a/sksmithy/tui/_components.py
+++ b/sksmithy/tui/_components.py
@@ -55,8 +55,9 @@ def on_input_change(self: Self, event: Input.Changed) -> None:
                 timeout=5,
             )
         else:
-            output_file = self.app.query_one("#output_file", Input)
-            output_file.value = f"{event.value.lower()}.py"
+            output_file = self.app.query_one("#output-file", Input)
+            if not output_file.value:
+                output_file.value = f"{event.value.lower()}.py"
 
 
 class Estimator(Container):
@@ -210,8 +211,8 @@ class DestinationFile(Container):
     """Destination file input component."""
 
     def compose(self: Self) -> ComposeResult:
-        yield Prompt(PROMPT_OUTPUT, classes="label", id="output_prompt")
-        yield Input(placeholder="mightyestimator.py", id="output_file")
+        yield Prompt(PROMPT_OUTPUT, classes="label")
+        yield Input(placeholder="mightyestimator.py", id="output-file")
 
 
 class ForgeButton(Container):
@@ -220,10 +221,10 @@ class ForgeButton(Container):
     def compose(self: Self) -> ComposeResult:
         yield Button.success(
             label="Forge ⚒️",
-            id="forge_btn",
+            id="forge-btn",
         )
 
-    @on(Button.Pressed, "#forge_btn")
+    @on(Button.Pressed, "#forge-btn")
     def on_forge(self: Self, _: Button.Pressed) -> None:  # noqa: C901
         errors = []
 
@@ -237,7 +238,7 @@ def on_forge(self: Self, _: Button.Pressed) -> None:  # noqa: C901
         predict_proba = self.app.query_one("#predict_proba", Switch).value
         decision_function = self.app.query_one("#decision_function", Switch).value
 
-        output_file = self.app.query_one("#output_file", Input).value
+        output_file = self.app.query_one("#output-file", Input).value
 
         match name_parser(name_input):
             case Ok(name):
@@ -249,7 +250,7 @@ def on_forge(self: Self, _: Button.Pressed) -> None:  # noqa: C901
             case str(v):
                 estimator_type = EstimatorType(v)
             case Select.BLANK:
-                errors.append("Estimator cannot be None!")
+                errors.append("Estimator cannot be empty!")
 
         match params_parser(required_params):
             case Ok(required):
@@ -311,10 +312,6 @@ class ForgeRow(Grid):
     """Row grid for forge."""
 
 
-
-forge_row = ForgeRow(Static(), Static(), ForgeButton(), DestinationFile(), Static(), Static(), id="forge_row")
-
-
 class Title(Static):
     pass
 
diff --git a/sksmithy/tui/_tui.py b/sksmithy/tui/_tui.py
index 6d6fb03..ae47015 100644
--- a/sksmithy/tui/_tui.py
+++ b/sksmithy/tui/_tui.py
@@ -5,11 +5,14 @@
 from textual.app import App, ComposeResult
 from textual.containers import Container, Horizontal, ScrollableContainer
 from textual.reactive import reactive
-from textual.widgets import Button, Footer, Header, Rule
+from textual.widgets import Button, Footer, Header, Rule, Static
 
 from sksmithy.tui._components import (
     DecisionFunction,
+    DestinationFile,
     Estimator,
+    ForgeButton,
+    ForgeRow,
     Linear,
     Name,
     Optional,
@@ -17,7 +20,6 @@
     Required,
     SampleWeight,
     Sidebar,
-    forge_row,
 )
 
 if sys.version_info >= (3, 11):  # pragma: no cover
@@ -41,6 +43,13 @@ class ForgeTUI(App):
 
     show_sidebar = reactive(False)  # noqa: FBT003
 
+    def on_mount(self: Self) -> None:
+        """Compose on mount.
+
+        Q: is this needed?
+        """
+        self.compose()
+
     def compose(self: Self) -> ComposeResult:
         """Create child widgets for the app."""
         yield Container(
@@ -51,18 +60,25 @@ def compose(self: Self) -> ComposeResult:
                 Horizontal(SampleWeight(), Linear()),
                 Horizontal(PredictProba(), DecisionFunction()),
                 Rule(),
-                forge_row,
+                ForgeRow(
+                    Static(),
+                    Static(),
+                    ForgeButton(),
+                    DestinationFile(),
+                    Static(),
+                    Static(),
+                ),
                 Rule(),
             ),
             Sidebar(classes="-hidden"),
             Footer(),
         )
 
-    def action_toggle_dark(self: Self) -> None:
+    def action_toggle_dark(self: Self) -> None:  # pragma: no cover
         """Toggle dark mode."""
         self.dark = not self.dark
 
-    def action_toggle_sidebar(self: Self) -> None:
+    def action_toggle_sidebar(self: Self) -> None:  # pragma: no cover
         """Toggle sidebar component."""
         sidebar = self.query_one(Sidebar)
         self.set_focus(None)
@@ -76,10 +92,10 @@ def action_toggle_sidebar(self: Self) -> None:
 
     def action_forge(self: Self) -> None:
         """Press forge button."""
-        forge_btn = self.query_one("#forge_btn", Button)
+        forge_btn = self.query_one("#forge-btn", Button)
         forge_btn.press()
 
 
-if __name__ == "__main__":
+if __name__ == "__main__":  # pragma: no cover
     tui = ForgeTUI()
     tui.run()
diff --git a/sksmithy/tui/_validators.py b/sksmithy/tui/_validators.py
index 8638b7f..8dc1eaa 100644
--- a/sksmithy/tui/_validators.py
+++ b/sksmithy/tui/_validators.py
@@ -17,7 +17,7 @@
 
 class _BaseValidator(Validator):
     @staticmethod
-    def parser(value: str) -> Result[str | list[str], str]:
+    def parser(value: str) -> Result[str | list[str], str]:  # pragma: no cover
         raise NotImplementedError
 
     def validate(self: Self, value: str) -> ValidationResult:
diff --git a/tests/conftest.py b/tests/conftest.py
index 4872254..e231dd9 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -19,6 +19,26 @@ def required(request: pytest.FixtureRequest) -> list[str]:
     return request.param
 
 
+@pytest.fixture(
+    params=[
+        ("a,a", "Found repeated parameters!"),
+        ("a-a", "The following parameters are invalid python identifiers: ('a-a',)"),
+    ]
+)
+def invalid_required(request: pytest.FixtureRequest) -> tuple[str, str]:
+    return request.param
+
+
+@pytest.fixture(
+    params=[
+        ("b,b", "Found repeated parameters!"),
+        ("b b", "The following parameters are invalid python identifiers: ('b b',)"),
+    ]
+)
+def invalid_optional(request: pytest.FixtureRequest) -> tuple[str, str]:
+    return request.param
+
+
 @pytest.fixture(params=[["mu", "sigma"], []])
 def optional(request: pytest.FixtureRequest) -> list[str]:
     return request.param
diff --git a/tests/test_tui.py b/tests/test_tui.py
new file mode 100644
index 0000000..ea9c7d1
--- /dev/null
+++ b/tests/test_tui.py
@@ -0,0 +1,178 @@
+from pathlib import Path
+
+import pytest
+from textual.widgets import Button, Input, Select, Switch
+
+from sksmithy._models import EstimatorType
+from sksmithy.tui import ForgeTUI
+
+
+async def test_smoke() -> None:
+    """Basic smoke test."""
+    app = ForgeTUI()
+    async with app.run_test(size=None) as pilot:
+        await pilot.pause()
+        assert pilot is not None
+
+        await pilot.pause()
+        await pilot.exit(0)
+
+
+@pytest.mark.parametrize(
+    ("name_", "err_msg"),
+    [
+        ("MightyEstimator", ""),
+        ("not-valid-name", "`not-valid-name` is not a valid python class name!"),
+        ("class", "`class` is a python reserved keyword!"),
+    ],
+)
+async def test_name(name_: str, err_msg: str) -> None:
+    """Test `name` text_input component."""
+    app = ForgeTUI()
+    async with app.run_test(size=None) as pilot:
+        name_comp = pilot.app.query_one("#name", Input)
+        name_comp.value = name_
+        await pilot.pause()
+
+        assert (not name_comp.is_valid) == bool(err_msg)
+
+        notifications = list(pilot.app._notifications)  # noqa: SLF001
+        assert len(notifications) == int(bool(err_msg))
+
+        if notifications:
+            assert notifications[0].message == err_msg
+
+
+async def test_estimator_interaction(estimator: EstimatorType) -> None:
+    """Test that all toggle components interact correctly with the selected estimator."""
+    app = ForgeTUI()
+    async with app.run_test(size=None) as pilot:
+        pilot.app.query_one("#estimator", Select).value = estimator.value
+        await pilot.pause()
+
+        assert (not pilot.app.query_one("#linear", Switch).disabled) == (
+            estimator in {EstimatorType.ClassifierMixin, EstimatorType.RegressorMixin}
+        )
+        assert (not pilot.app.query_one("#predict_proba", Switch).disabled) == (
+            estimator in {EstimatorType.ClassifierMixin, EstimatorType.OutlierMixin}
+        )
+
+        assert (not pilot.app.query_one("#decision_function", Switch).disabled) == (
+            estimator == EstimatorType.ClassifierMixin
+        )
+
+        if estimator == EstimatorType.ClassifierMixin:
+            linear = pilot.app.query_one("#linear", Switch)
+            linear.value = True
+
+            await pilot.pause()
+            assert pilot.app.query_one("#decision_function", Switch).disabled
+
+
+async def test_valid_params() -> None:
+    """Test required and optional params interaction."""
+    app = ForgeTUI()
+    required_ = "a,b"
+    optional_ = "c,d"
+    async with app.run_test(size=None) as pilot:
+        required_comp = pilot.app.query_one("#required", Input)
+        optional_comp = pilot.app.query_one("#optional", Input)
+
+        required_comp.value = required_
+        optional_comp.value = optional_
+
+        await required_comp.action_submit()
+        await optional_comp.action_submit()
+        await pilot.pause(0.01)
+
+        notifications = list(pilot.app._notifications)  # noqa: SLF001
+        assert not notifications
+
+
+@pytest.mark.parametrize(("required_", "optional_"), [("a,b", "a"), ("a", "a,b")])
+async def test_duplicated_params(required_: str, optional_: str) -> None:
+    app = ForgeTUI()
+    msg = "The following parameters are duplicated between required and optional: {'a'}"
+
+    async with app.run_test(size=None) as pilot:
+        required_comp = pilot.app.query_one("#required", Input)
+        optional_comp = pilot.app.query_one("#optional", Input)
+
+        required_comp.value = required_
+        optional_comp.value = optional_
+
+        await required_comp.action_submit()
+        await optional_comp.action_submit()
+        await pilot.pause()
+
+        forge_btn = pilot.app.query_one("#forge-btn", Button)
+        forge_btn.action_press()
+        await pilot.pause()
+
+        assert all(msg in n.message for n in pilot.app._notifications)  # noqa: SLF001
+
+
+async def test_forge_raise() -> None:
+    """Test forge button and all of its interactions."""
+    app = ForgeTUI()
+    async with app.run_test(size=None) as pilot:
+        required_comp = pilot.app.query_one("#required", Input)
+        optional_comp = pilot.app.query_one("#optional", Input)
+
+        required_comp.value = "a,a"
+        optional_comp.value = "b b"
+
+        await required_comp.action_submit()
+        await optional_comp.action_submit()
+        await pilot.pause()
+
+        forge_btn = pilot.app.query_one("#forge-btn", Button)
+        forge_btn.action_press()
+        await pilot.pause()
+
+        m1, m2, m3 = (n.message for n in pilot.app._notifications)  # noqa: SLF001
+
+        assert "Found repeated parameters!" in m1
+        assert "The following parameters are invalid python identifiers: ('b b',)" in m2
+
+        assert "Name cannot be empty!" in m3
+        assert "Estimator cannot be empty!" in m3
+        assert "Outfile file cannot be empty!" in m3
+        assert "Found repeated parameters!" in m3
+        assert "The following parameters are invalid python identifiers: ('b b',)" in m3
+
+
+@pytest.mark.parametrize("use_binding", [True, False])
+async def test_forge(tmp_path: Path, use_binding: bool) -> None:
+    """Test forge button and all of its interactions."""
+    app = ForgeTUI()
+    name = "MightyEstimator"
+    estimator = "classifier"
+    async with app.run_test(size=None) as pilot:
+        name_comp = pilot.app.query_one("#name", Input)
+        estimator_comp = pilot.app.query_one("#estimator", Select)
+        await pilot.pause()
+
+        output_file_comp = pilot.app.query_one("#output-file", Input)
+
+        name_comp.value = name
+        estimator_comp.value = estimator
+
+        await pilot.pause()
+
+        output_file = tmp_path / (f"{name.lower()}.py")
+        output_file_comp.value = str(output_file)
+        await output_file_comp.action_submit()
+        await pilot.pause()
+
+        if use_binding:
+            await pilot.press("F")
+        else:
+            forge_btn = pilot.app.query_one("#forge-btn", Button)
+            forge_btn.action_press()
+        await pilot.pause()
+
+        notification = next(iter(pilot.app._notifications))  # noqa: SLF001
+
+        assert f"Template forged at {output_file!s}" in notification.message
+        assert output_file.exists()