diff --git a/data_only_viz/tests/test_state_smplxperson.py b/data_only_viz/tests/test_state_smplxperson.py
new file mode 100644
index 0000000..ee113aa
--- /dev/null
+++ b/data_only_viz/tests/test_state_smplxperson.py
@@ -0,0 +1,35 @@
+"""SMPLXPerson fields are numpy float32 arrays after Plan 1 Tasks 5 & 6."""
+
+import numpy as np
+
+from data_only_viz.state import SMPLXPerson
+
+
+def test_smplxperson_accepts_ndarrays():
+    p = SMPLXPerson(
+        pid=0,
+        confidence=1.0,
+        translation=np.zeros(3, dtype=np.float32),
+        betas=np.zeros(10, dtype=np.float32),
+        expression=np.zeros(10, dtype=np.float32),
+        vertices_3d=np.zeros((10475, 3), dtype=np.float32),
+    )
+    assert isinstance(p.vertices_3d, np.ndarray)
+    assert p.vertices_3d.dtype == np.float32
+    assert p.vertices_3d.shape == (10475, 3)
+    assert isinstance(p.translation, np.ndarray)
+    assert isinstance(p.betas, np.ndarray)
+    assert isinstance(p.expression, np.ndarray)
+
+
+def test_smplxperson_does_not_have_joints_3d():
+    """Plan 1 Task 6 removed the joints_3d field."""
+    p = SMPLXPerson(
+        pid=0,
+        confidence=1.0,
+        translation=np.zeros(3, dtype=np.float32),
+        betas=np.zeros(10, dtype=np.float32),
+        expression=np.zeros(10, dtype=np.float32),
+        vertices_3d=np.zeros((10475, 3), dtype=np.float32),
+    )
+    assert not hasattr(p, "joints_3d"), "joints_3d was removed in Plan 1 Task 6"