diff --git a/zixy/src/container/word_iters/_word_iters.rs b/zixy/src/container/word_iters/_word_iters.rs
index 45ae010..d9a3995 100644
--- a/zixy/src/container/word_iters/_word_iters.rs
+++ b/zixy/src/container/word_iters/_word_iters.rs
@@ -567,7 +567,7 @@ pub mod test_defs {
 }
 
 #[cfg(test)]
-pub mod tests {
+mod tests {
     use crate::container::quicksort::QuickSortNoCoeffs;
     use rand::rngs::StdRng;
     use rand::{Rng, SeedableRng};
diff --git a/zixy/src/container/word_iters/term_set.rs b/zixy/src/container/word_iters/term_set.rs
index b567d05..f4ffa01 100644
--- a/zixy/src/container/word_iters/term_set.rs
+++ b/zixy/src/container/word_iters/term_set.rs
@@ -761,7 +761,7 @@ pub mod test_defs {
 }
 
 #[cfg(test)]
-pub mod tests {
+mod tests {
     use super::test_defs::StringCmpnts;
     use crate::container::{
         traits::EmptyFrom,
diff --git a/zixy/src/qubit/traits.rs b/zixy/src/qubit/traits.rs
index c88e585..a4a4703 100644
--- a/zixy/src/qubit/traits.rs
+++ b/zixy/src/qubit/traits.rs
@@ -190,11 +190,7 @@ pub trait PauliWordRef: QubitsBased + Display {
     fn get_pauli_unchecked(&self, i_mode: usize) -> PauliMatrix;
     /// Return the Pauli matrix at `i_mode`, or `OutOfBounds` if `i_mode` is invalid.
     fn get_pauli(&self, i_mode: usize) -> Result<PauliMatrix, OutOfBounds> {
-        OutOfBounds::check(
-            i_mode,
-            self.get_container().qubits().len(),
-            Dimension::Cmpnt,
-        )?;
+        OutOfBounds::check(i_mode, self.get_container().qubits().len(), Dimension::Mode)?;
         Ok(self.get_pauli_unchecked(i_mode))
     }
 
@@ -508,3 +504,246 @@ pub trait PauliWordMutRef: QubitsBased {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use core::fmt;
+
+    use super::*;
+
+    #[derive(Clone)]
+    struct TestContainer {
+        qubits: Qubits,
+        calls: Vec<&'static str>,
+    }
+
+    impl TestContainer {
+        fn new(qubits: Qubits) -> Self {
+            Self {
+                qubits,
+                calls: vec![],
+            }
+        }
+
+        fn new_from_count(n: usize) -> Self {
+            Self::new(Qubits::from_count(n))
+        }
+
+        fn new_from_offset(i: usize, n: usize) -> Self {
+            Self::new(Qubits::from_offset(i, n))
+        }
+    }
+
+    impl QubitsBased for TestContainer {
+        fn qubits(&self) -> &Qubits {
+            &self.qubits
+        }
+    }
+
+    impl proj::ToOwned for TestContainer {
+        type OwnedType = Self;
+        fn to_owned(&self) -> Self {
+            self.clone()
+        }
+    }
+
+    impl QubitsStandardized for TestContainer {}
+
+    impl QubitsStandardize for TestContainer {
+        fn general_standardize(&mut self, n_qubit: usize) {
+            self.calls.push("general");
+            self.qubits = Qubits::from_count(n_qubit);
+        }
+
+        fn resize_standardize(&mut self, n_qubit: usize) {
+            self.calls.push("resize");
+            self.qubits = Qubits::from_count(n_qubit);
+        }
+    }
+
+    impl QubitsRelabel for TestContainer {
+        fn qubits_mut(&mut self) -> &mut Qubits {
+            &mut self.qubits
+        }
+    }
+
+    struct TestPauliWord {
+        qubits: Qubits,
+        paulis: Vec<PauliMatrix>,
+    }
+
+    impl TestPauliWord {
+        fn new(paulis: Vec<PauliMatrix>) -> Self {
+            Self {
+                qubits: Qubits::from_count(paulis.len()),
+                paulis,
+            }
+        }
+    }
+
+    impl QubitsBased for TestPauliWord {
+        fn qubits(&self) -> &Qubits {
+            &self.qubits
+        }
+    }
+
+    impl PauliWordMutRef for TestPauliWord {
+        fn set_pauli_unchecked(&mut self, i_mode: usize, pauli: PauliMatrix) {
+            self.paulis[i_mode] = pauli;
+        }
+
+        fn get_pauli_unchecked(&self, i_mode: usize) -> PauliMatrix {
+            self.paulis[i_mode]
+        }
+    }
+
+    impl fmt::Display for TestPauliWord {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            write!(
+                f,
+                "TestPauliWord with qubits {:?} and paulis {:?}",
+                self.qubits, self.paulis
+            )
+        }
+    }
+
+    impl PauliWordRef for TestPauliWord {
+        type T = Self;
+        fn get_container(&self) -> &Self::T {
+            self
+        }
+
+        fn get_pauli_unchecked(&self, i_mode: usize) -> PauliMatrix {
+            self.paulis[i_mode]
+        }
+
+        fn count(&self, pauli: PauliMatrix) -> usize {
+            self.paulis.iter().filter(|&&p| p == pauli).count()
+        }
+    }
+
+    #[test]
+    fn test_standardize_calls() {
+        let mut test = TestContainer::new_from_count(2);
+
+        test.standardize(5);
+        assert_eq!(test.calls, vec!["resize"]);
+        assert_eq!(test.qubits, Qubits::from_count(5));
+    }
+
+    #[test]
+    fn test_standardize_uses_general() {
+        let mut test = TestContainer::new_from_offset(2, 3);
+
+        test.standardize(3);
+        assert_eq!(test.calls, vec!["general"]);
+        assert_eq!(test.qubits, Qubits::from_count(3));
+    }
+
+    #[test]
+    fn test_standardize_no_op() {
+        let mut test = TestContainer::new_from_count(3);
+
+        test.standardize(3);
+        assert!(test.calls.is_empty());
+        assert_eq!(test.qubits, Qubits::from_count(3));
+    }
+
+    #[test]
+    fn test_general_standardized() {
+        let test = TestContainer::new_from_count(3);
+
+        let standardized = test.general_standardized(4);
+        assert!(test.calls.is_empty());
+        assert_eq!(standardized.calls, vec!["general"]);
+        assert_eq!(standardized.qubits, Qubits::from_count(4));
+    }
+
+    #[test]
+    fn test_resize_standardized() {
+        let test = TestContainer::new_from_count(3);
+        let standardized = test.resize_standardized(2);
+        assert!(test.calls.is_empty());
+        assert_eq!(standardized.calls, vec!["resize"]);
+        assert_eq!(standardized.qubits, Qubits::from_count(2));
+        assert_eq!(test.qubits, Qubits::from_count(3));
+    }
+
+    #[test]
+    fn test_push_standardized() {
+        let test = TestContainer::new_from_count(3);
+        let standardized = test.push_standardized();
+        assert!(test.calls.is_empty());
+        assert_eq!(standardized.calls, vec!["resize"]);
+        assert_eq!(standardized.qubits, Qubits::from_count(4));
+        assert_eq!(test.qubits, Qubits::from_count(3));
+    }
+
+    #[test]
+    fn test_relabelled() -> Result<(), BasisError> {
+        let mut test = TestContainer::new_from_count(3);
+        test.relabel(Qubits::from_offset(4, 3))?;
+        assert_eq!(test.qubits, Qubits::from_offset(4, 3));
+        Ok(())
+    }
+
+    #[test]
+    fn test_relabel_invalid() {
+        let mut test = TestContainer::new_from_count(3);
+        let result = test.relabel(Qubits::from_count(4));
+        assert!(matches!(result, Err(BasisError::Counts(_))));
+        assert_eq!(test.qubits, Qubits::from_count(3));
+    }
+
+    #[test]
+    fn test_pauliword_clear() {
+        let mut test = TestPauliWord::new(vec![
+            PauliMatrix::X,
+            PauliMatrix::Y,
+            PauliMatrix::Z,
+            PauliMatrix::I,
+        ]);
+        test.clear();
+        assert_eq!(test.paulis, vec![PauliMatrix::I; 4]);
+    }
+
+    #[test]
+    fn test_pauliword_map() {
+        let test = TestPauliWord::new(vec![
+            PauliMatrix::X,
+            PauliMatrix::Y,
+            PauliMatrix::I,
+            PauliMatrix::X,
+            PauliMatrix::I,
+        ]);
+        let map = test.get_pauli_map();
+        assert_eq!(map.len(), 3);
+        assert_eq!(map[&0], PauliMatrix::X);
+        assert_eq!(map[&3], PauliMatrix::X);
+        assert_eq!(map[&1], PauliMatrix::Y);
+    }
+
+    #[test]
+    fn test_setpaulimap() -> Result<(), OutOfBounds> {
+        let mut test = TestPauliWord::new(vec![PauliMatrix::I; 3]);
+        let mut map = HashMap::new();
+        map.insert(1, PauliMatrix::X);
+        map.insert(2, PauliMatrix::Y);
+        test.set_pauli_map(map)?;
+        assert_eq!(
+            test.paulis,
+            vec![PauliMatrix::I, PauliMatrix::X, PauliMatrix::Y]
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn test_setpaulimap_invalid() {
+        let mut test = TestPauliWord::new(vec![PauliMatrix::I; 3]);
+        let mut map = HashMap::new();
+        map.insert(100, PauliMatrix::Y); // invalid for word of length 3
+        let result = test.set_pauli_map(map);
+        assert!(result.is_err());
+        assert_eq!(test.paulis, vec![PauliMatrix::I; 3]);
+    }
+}