UI improvements + add axis orientation test

- Rename app to 'Motief: de stematlas' in Home.py
- Remove PCA variance caption from compass tab
- Hardcode db_path and window_size; remove sidebar inputs
- Change trajectories default to [CDA, D66, VVD]
- Move quiz to pages/1_Stemwijzer.py; wrap in st.form
- Remove quiz tab from main explorer
- Add pytest dev dep + fix test fixtures (_load_mp_vectors_for_window)
- Add test_pca_axis_orientation with proper PCA variance dominance

Home.py

@@ -7,7 +7,7 @@ brief descriptions of and links to the two sub-pages.
 import streamlit as st
 
 st.set_page_config(
-    page_title="StemAtlas",
+    page_title="Motief: de stematlas",
     page_icon="🗺️",
     layout="centered",
     initial_sidebar_state="expanded",
@@ -15,9 +15,9 @@ st.set_page_config(
 
 
 def main() -> None:
-    st.title("🗺️ StemAtlas")
+    st.title("🗺️ Motief: de stematlas")
     st.markdown(
-        "**StemAtlas** brengt de Nederlandse Tweede Kamer in kaart op basis van "
+        "**Motief** brengt de Nederlandse Tweede Kamer in kaart op basis van "
         "echte stemmingen over moties. Gebruik de Stemwijzer om te ontdekken welke "
         "partij het beste bij jouw standpunten past, of verken de politieke ruimte "
         "zelf in de Explorer."

explorer.py

@@ -840,14 +840,6 @@ def build_compass_tab(db_path: str, window_size: str) -> None:
     with col1:
         st.plotly_chart(fig, use_container_width=True)
 
-    # Axis info
-    if axis_def:
-        evr = axis_def.get("explained_variance_ratio", [])
-        if evr:
-            st.caption(
-                f"PCA verklaarde variantie: as 1 = {evr[0] * 100:.1f}%, as 2 = {evr[1] * 100:.1f}%"
-            )
-
 
 # ---------------------------------------------------------------------------
 # Tab 2: Partij Trajectories
@@ -888,9 +880,10 @@ def build_trajectories_tab(db_path: str, window_size: str) -> None:
 
     all_parties_sorted = sorted(all_parties)
 
-    # Default: prefer known major parties over the automatic "appeared in most windows"
+    # Default: show CDA, D66, VVD — the three parties that span the political centre
-    # heuristic, which would exclude newer parties like NSC that only have 4 windows.
+    default_parties = [p for p in ["CDA", "D66", "VVD"] if p in all_parties]
-    default_parties = [p for p in KNOWN_MAJOR_PARTIES if p in all_parties]
+    if not default_parties:
+        default_parties = [p for p in KNOWN_MAJOR_PARTIES if p in all_parties]
     if not default_parties:
         default_parties = all_parties_sorted[:6]
 
@@ -1541,7 +1534,8 @@ def build_mp_quiz_tab(db_path: str) -> None:
             st.session_state["mp_quiz_asked"] = []
             st.rerun()
 
-    # main question loop (single question per render)
+    # main question loop (single question per render, wrapped in a form to avoid
+    # premature reruns when the user changes the radio selection)
     next_mid = _next_motion_id()
     if next_mid is None:
         st.info("Geen nieuwe vragen beschikbaar om kandidaten te scheiden.")
@@ -1557,14 +1551,15 @@ def build_mp_quiz_tab(db_path: str) -> None:
         if motion_row.get("layman_explanation"):
             st.info(motion_row.get("layman_explanation"))
 
-        choice = st.radio(
+        with st.form(key=f"mp_quiz_form_{next_mid}"):
-            "Wat zou jij stemmen?",
+            choice = st.radio(
-            options=["Voor", "Tegen", "Onthouden", "Geen stem"],
+                "Wat zou jij stemmen?",
-            index=3,
+                options=["Voor", "Tegen", "Onthouden", "Geen stem"],
-            key=f"mp_quiz_choice_{next_mid}",
+                index=3,
-        )
+            )
+            submitted = st.form_submit_button("Beantwoord en verder")
 
-        if st.button("Beantwoord en verder", key=f"mp_quiz_submit_{next_mid}"):
+        if submitted:
             st.session_state["mp_quiz_votes"][str(next_mid)] = choice
             st.session_state["mp_quiz_asked"].append(next_mid)
             st.rerun()
@@ -1617,13 +1612,8 @@ def run_app() -> None:
 
     # Sidebar
     st.sidebar.title("Instellingen")
-    db_path = st.sidebar.text_input("DuckDB pad", value="data/motions.db")
+    db_path = "data/motions.db"
-    window_size = st.sidebar.radio(
+    window_size = "annual"
-        "Venstergrootte",
-        options=["annual", "quarterly"],
-        format_func=lambda x: "Per jaar" if x == "annual" else "Per kwartaal",
-        index=0,
-    )
     show_rejected = st.sidebar.checkbox("Toon verworpen moties", value=False)
 
     # About section
@@ -1649,12 +1639,11 @@ def run_app() -> None:
         "📈 Trajectories",
         "🔍 Motie Zoeken",
         "📋 Motie Browser",
-        "🧑‍⚖️ Welk tweede kamerlid ben jij?",
         "🔬 SVD Components",
     ]
 
     if hasattr(st, "tabs") and callable(getattr(st, "tabs")):
-        tab1, tab2, tab3, tab4, tab5, tab6 = st.tabs(tab_labels)
+        tab1, tab2, tab3, tab4, tab5 = st.tabs(tab_labels)
         with tab1:
             build_compass_tab(db_path, window_size)
         with tab2:
@@ -1664,8 +1653,6 @@ def run_app() -> None:
         with tab4:
             build_browser_tab(db_path, show_rejected)
         with tab5:
-            build_mp_quiz_tab(db_path)
-        with tab6:
             build_svd_components_tab(db_path)
     else:
         # Fallback for environments where `st.tabs` is not available: use a radio selector
@@ -1678,8 +1665,6 @@ def run_app() -> None:
             build_search_tab(db_path, show_rejected)
         elif selection == tab_labels[3]:
             build_browser_tab(db_path, show_rejected)
-        elif selection == tab_labels[4]:
-            build_mp_quiz_tab(db_path)
         else:
             build_svd_components_tab(db_path)
 

pages/1_Stemwijzer.py

@@ -1,5 +1,13 @@
-"""Stemwijzer page — thin wrapper around the existing app module."""
+"""Stemwijzer page — quiz to find your matching MP."""
 
-from app import main  # noqa: F401  (module-level set_page_config runs on import)
+import streamlit as st
 
-main()
+st.set_page_config(
+    page_title="Stemwijzer",
+    page_icon="🗳️",
+    layout="centered",
+)
+
+from explorer import build_mp_quiz_tab
+
+build_mp_quiz_tab("data/motions.db")

pyproject.toml

@@ -19,3 +19,8 @@ dependencies = [
     "beautifulsoup4>=4.14.3",
     "lxml>=6.0.2",
 ]
+
+[dependency-groups]
+dev = [
+    "pytest>=9.0.2",
+]

tests/test_political_compass.py

@@ -5,6 +5,19 @@ import sys
 import pytest
 
 
+# ---------------------------------------------------------------------------
+# Helpers shared by orientation tests
+# ---------------------------------------------------------------------------
+
+
+def _make_fake_traj(aligned):
+    fake = types.SimpleNamespace()
+    fake._load_window_ids = lambda db: list(aligned.keys())
+    fake._load_mp_vectors_for_window = lambda db, w: aligned.get(w, {})
+    fake._procrustes_align_windows = lambda x: aligned
+    return fake
+
+
 def test_compute_2d_axes_pca_synthetic(monkeypatch):
     """Synthetic test for compute_2d_axes using patched alignment helper."""
 
@@ -14,15 +27,15 @@ def test_compute_2d_axes_pca_synthetic(monkeypatch):
     # _load_window_ids should return ordered windows
     fake_traj._load_window_ids = lambda db: ["w1", "w2"]
 
-    # _load_mp_vectors_for_window is not used because we patch _procrustes_align_windows
-    fake_traj._load_mp_vectors_for_window = lambda db, w: {}
-
     # Provide aligned vectors directly
     aligned = {
         "w1": {"Alice": np.array([1.0, 0.0, 0.0]), "Bob": np.array([0.0, 1.0, 0.0])},
         "w2": {"Alice": np.array([0.8, 0.2, 0.0]), "Bob": np.array([0.1, 0.9, 0.0])},
     }
 
+    # _load_mp_vectors_for_window returns the pre-aligned vectors (needed for padding step)
+    fake_traj._load_mp_vectors_for_window = lambda db, w: aligned.get(w, {})
+
     fake_traj._procrustes_align_windows = lambda x: aligned
 
     # Insert fake module into sys.modules for import by analysis.political_axis
@@ -42,3 +55,95 @@ def test_compute_2d_axes_pca_synthetic(monkeypatch):
             assert np.isfinite(coord[0]) and np.isfinite(coord[1])
 
     assert axis_def.get("method") == "pca"
+
+
+def test_pca_axis_orientation(monkeypatch):
+    """PCA axes must be oriented so right parties score higher on X and
+    progressive parties score higher on Y than their respective opposites.
+
+    We construct a minimal vote-matrix world where:
+    - Right MPs (PVV, VVD members) cluster in one direction on dim-0.
+    - Left MPs (SP, GroenLinks-PvdA members) cluster in the opposite direction.
+    - Progressive MPs cluster on dim-1; conservative MPs on the opposite side.
+
+    The orientation logic in compute_2d_axes should flip axis signs so that
+    right_x > left_x and prog_y > cons_y regardless of the raw SVD sign.
+    """
+    # Build vectors so that right parties are at +1 on dim-0 and
+    # progressive parties are at +1 on dim-1.
+    # We deliberately negate them to test that auto-orient flips them back.
+    # Right/left use magnitude 3, prog/cons use magnitude 1 so that dim-0
+    # dominates PCA variance — ensuring PC1 = left-right axis, PC2 = prog-cons.
+    right_vec = np.array([-3.0, 0.0, 0.0])  # intentionally negative on dim-0
+    left_vec = np.array([3.0, 0.0, 0.0])  # intentionally positive on dim-0
+    prog_vec = np.array([0.0, -1.0, 0.0])  # intentionally negative on dim-1
+    cons_vec = np.array([0.0, 1.0, 0.0])  # intentionally positive on dim-1
+
+    aligned = {
+        "w1": {
+            # Right-leaning MPs
+            "Wilders, G.": right_vec,
+            "Rutte, M.": right_vec + np.array([0.0, 0.0, 0.05]),
+            # Left-leaning MPs
+            "Marijnissen, L.": left_vec,
+            "Klever, A.": left_vec + np.array([0.0, 0.0, 0.05]),
+            # Progressive MPs
+            "Bromet, L.": prog_vec,
+            "Nijboer, H.": prog_vec + np.array([0.0, 0.0, -0.05]),
+            # Conservative MPs
+            "Segers, G.": cons_vec,
+            "Omtzigt, P.": cons_vec + np.array([0.0, 0.0, -0.05]),
+        }
+    }
+
+    # mp_metadata rows used by the orientation code (party affiliation)
+    mp_metadata = [
+        ("Wilders, G.", "PVV"),
+        ("Rutte, M.", "VVD"),
+        ("Marijnissen, L.", "SP"),
+        ("Klever, A.", "GroenLinks-PvdA"),
+        ("Bromet, L.", "GroenLinks-PvdA"),
+        ("Nijboer, H.", "SP"),
+        ("Segers, G.", "CDA"),
+        ("Omtzigt, P.", "Nieuw Sociaal Contract"),
+    ]
+
+    fake_traj = _make_fake_traj(aligned)
+    monkeypatch.setitem(sys.modules, "analysis.trajectory", fake_traj)
+
+    # Patch duckdb so the orientation helper can fetch mp_metadata
+    import types as _types
+
+    fake_conn = _types.SimpleNamespace(
+        execute=lambda q: _types.SimpleNamespace(fetchall=lambda: mp_metadata),
+        close=lambda: None,
+    )
+    import duckdb as _duckdb
+
+    monkeypatch.setattr(_duckdb, "connect", lambda db_path, **kw: fake_conn)
+
+    # Need to reload the module so monkeypatched sys.modules takes effect
+    import importlib, analysis.political_axis as _ax
+
+    importlib.reload(_ax)
+    from analysis.political_axis import compute_2d_axes
+
+    positions_by_window, axis_def = compute_2d_axes(
+        db_path="dummy", window_ids=["w1"], method="pca"
+    )
+
+    pos = positions_by_window["w1"]
+
+    # X-axis: right parties should score higher than left parties
+    right_x = np.mean([pos["Wilders, G."][0], pos["Rutte, M."][0]])
+    left_x = np.mean([pos["Marijnissen, L."][0], pos["Klever, A."][0]])
+    assert right_x > left_x, (
+        f"Expected right parties (x={right_x:.3f}) > left parties (x={left_x:.3f}) on X-axis"
+    )
+
+    # Y-axis: progressive parties should score higher than conservative parties
+    prog_y = np.mean([pos["Bromet, L."][1], pos["Nijboer, H."][1]])
+    cons_y = np.mean([pos["Segers, G."][1], pos["Omtzigt, P."][1]])
+    assert prog_y > cons_y, (
+        f"Expected progressive parties (y={prog_y:.3f}) > conservative parties (y={cons_y:.3f}) on Y-axis"
+    )

uv.lock

@@ -273,6 +273,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/76/c6/c88e154df9c4e1a2a66ccf0005a88dfb2650c1dffb6f5ce603dfbd452ce3/idna-3.10-py3-none-any.whl", hash = "sha256:946d195a0d259cbba61165e88e65941f16e9b36ea6ddb97f00452bae8b1287d3", size = 70442, upload-time = "2024-09-15T18:07:37.964Z" },
 ]
 
+[[package]]
+name = "iniconfig"
+version = "2.3.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/72/34/14ca021ce8e5dfedc35312d08ba8bf51fdd999c576889fc2c24cb97f4f10/iniconfig-2.3.0.tar.gz", hash = "sha256:c76315c77db068650d49c5b56314774a7804df16fee4402c1f19d6d15d8c4730", size = 20503, upload-time = "2025-10-18T21:55:43.219Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/cb/b1/3846dd7f199d53cb17f49cba7e651e9ce294d8497c8c150530ed11865bb8/iniconfig-2.3.0-py3-none-any.whl", hash = "sha256:f631c04d2c48c52b84d0d0549c99ff3859c98df65b3101406327ecc7d53fbf12", size = 7484, upload-time = "2025-10-18T21:55:41.639Z" },
+]
+
 [[package]]
 name = "jinja2"
 version = "3.1.6"
@@ -697,6 +706,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/52/d2/c6e44dba74f17c6216ce1b56044a9b93a929f1c2d5bdaff892512b260f5e/plotly-6.6.0-py3-none-any.whl", hash = "sha256:8d6daf0f87412e0c0bfe72e809d615217ab57cc715899a1e5145135a7800d1d0", size = 9910315, upload-time = "2026-03-02T21:10:18.131Z" },
 ]
 
+[[package]]
+name = "pluggy"
+version = "1.6.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/f9/e2/3e91f31a7d2b083fe6ef3fa267035b518369d9511ffab804f839851d2779/pluggy-1.6.0.tar.gz", hash = "sha256:7dcc130b76258d33b90f61b658791dede3486c3e6bfb003ee5c9bfb396dd22f3", size = 69412, upload-time = "2025-05-15T12:30:07.975Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/54/20/4d324d65cc6d9205fabedc306948156824eb9f0ee1633355a8f7ec5c66bf/pluggy-1.6.0-py3-none-any.whl", hash = "sha256:e920276dd6813095e9377c0bc5566d94c932c33b27a3e3945d8389c374dd4746", size = 20538, upload-time = "2025-05-15T12:30:06.134Z" },
+]
+
 [[package]]
 name = "protobuf"
 version = "6.31.1"
@@ -823,6 +841,22 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/b2/e6/94145d714402fd5ade00b5661f2d0ab981219e07f7db9bfa16786cdb9c04/pynndescent-0.6.0-py3-none-any.whl", hash = "sha256:dc8c74844e4c7f5cbd1e0cd6909da86fdc789e6ff4997336e344779c3d5538ef", size = 73511, upload-time = "2026-01-08T21:29:57.306Z" },
 ]
 
+[[package]]
+name = "pytest"
+version = "9.0.2"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "colorama", marker = "sys_platform == 'win32'" },
+    { name = "iniconfig" },
+    { name = "packaging" },
+    { name = "pluggy" },
+    { name = "pygments" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/d1/db/7ef3487e0fb0049ddb5ce41d3a49c235bf9ad299b6a25d5780a89f19230f/pytest-9.0.2.tar.gz", hash = "sha256:75186651a92bd89611d1d9fc20f0b4345fd827c41ccd5c299a868a05d70edf11", size = 1568901, upload-time = "2025-12-06T21:30:51.014Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/3b/ab/b3226f0bd7cdcf710fbede2b3548584366da3b19b5021e74f5bde2a8fa3f/pytest-9.0.2-py3-none-any.whl", hash = "sha256:711ffd45bf766d5264d487b917733b453d917afd2b0ad65223959f59089f875b", size = 374801, upload-time = "2025-12-06T21:30:49.154Z" },
+]
+
 [[package]]
 name = "python-dateutil"
 version = "2.9.0.post0"
@@ -1113,6 +1147,11 @@ dependencies = [
     { name = "umap-learn" },
 ]
 
+[package.dev-dependencies]
+dev = [
+    { name = "pytest" },
+]
+
 [package.metadata]
 requires-dist = [
     { name = "beautifulsoup4", specifier = ">=4.14.3" },
@@ -1129,6 +1168,9 @@ requires-dist = [
     { name = "umap-learn", specifier = ">=0.5" },
 ]
 
+[package.metadata.requires-dev]
+dev = [{ name = "pytest", specifier = ">=9.0.2" }]
+
 [[package]]
 name = "streamlit"
 version = "1.48.0"