diff --git a/nalgebra-sparse/src/csr.rs b/nalgebra-sparse/src/csr.rs
index 8c4be726..c612e5b4 100644
--- a/nalgebra-sparse/src/csr.rs
+++ b/nalgebra-sparse/src/csr.rs
@@ -62,7 +62,7 @@ impl<T> CsrMatrix<T> {
 
     /// The column indices defining part of the CSR format.
     #[inline]
-    pub fn column_indices(&self) -> &[usize] {
+    pub fn col_indices(&self) -> &[usize] {
         self.sparsity_pattern.minor_indices()
     }
 
@@ -520,7 +520,7 @@ where
     type Item = CsrRowMut<'a, T>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        let lane = self.pattern.lane(self.current_row_idx);
+        let lane = self.pattern.get_lane(self.current_row_idx);
         let ncols = self.pattern.minor_dim();
 
         if let Some(col_indices) = lane {
diff --git a/nalgebra-sparse/src/lib.rs b/nalgebra-sparse/src/lib.rs
index 872126a8..9621d973 100644
--- a/nalgebra-sparse/src/lib.rs
+++ b/nalgebra-sparse/src/lib.rs
@@ -103,7 +103,7 @@ impl SparseFormatError {
 }
 
 /// The type of format error described by a [SparseFormatError](struct.SparseFormatError.html).
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum SparseFormatErrorKind {
     /// Indicates that the index data associated with the format contains at least one index
     /// out of bounds.
diff --git a/nalgebra-sparse/src/pattern.rs b/nalgebra-sparse/src/pattern.rs
index 54e0f2e8..f95f23c8 100644
--- a/nalgebra-sparse/src/pattern.rs
+++ b/nalgebra-sparse/src/pattern.rs
@@ -66,8 +66,19 @@ impl SparsityPattern {
     }
 
     /// Get the lane at the given index.
+    ///
+    /// Panics
+    /// ------
+    ///
+    /// Panics if `major_index` is out of bounds.
     #[inline]
-    pub fn lane(&self, major_index: usize) -> Option<&[usize]> {
+    pub fn lane(&self, major_index: usize) -> &[usize] {
+        self.get_lane(major_index).unwrap()
+    }
+
+    /// Get the lane at the given index, or `None` if out of bounds.
+    #[inline]
+    pub fn get_lane(&self, major_index: usize) -> Option<&[usize]> {
         let offset_begin = *self.major_offsets().get(major_index)?;
         let offset_end = *self.major_offsets().get(major_index + 1)?;
         Some(&self.minor_indices()[offset_begin..offset_end])
@@ -124,7 +135,7 @@ impl SparsityPattern {
                 let mut prev = None;
 
                 while let Some(next) = iter.next().copied() {
-                    if next > minor_dim {
+                    if next >= minor_dim {
                         return Err(MinorIndexOutOfBounds);
                     }
 
@@ -197,7 +208,7 @@ impl SparsityPattern {
 
 /// Error type for `SparsityPattern` format errors.
 #[non_exhaustive]
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum SparsityPatternFormatError {
     /// Indicates an invalid number of offsets.
     ///
diff --git a/nalgebra-sparse/tests/unit_tests/csr.rs b/nalgebra-sparse/tests/unit_tests/csr.rs
new file mode 100644
index 00000000..693e092f
--- /dev/null
+++ b/nalgebra-sparse/tests/unit_tests/csr.rs
@@ -0,0 +1,231 @@
+use nalgebra_sparse::csr::CsrMatrix;
+use nalgebra_sparse::SparseFormatErrorKind;
+
+#[test]
+fn csr_matrix_valid_data() {
+    // Construct matrix from valid data and check that selected methods return results
+    // that agree with expectations.
+
+    {
+        // A CSR matrix with zero explicitly stored entries
+        let offsets = vec![0, 0, 0, 0];
+        let indices = vec![];
+        let values = Vec::<i32>::new();
+        let mut matrix = CsrMatrix::try_from_csr_data(3, 2, offsets, indices, values).unwrap();
+
+        assert_eq!(matrix, CsrMatrix::new(3, 2));
+
+        assert_eq!(matrix.nrows(), 3);
+        assert_eq!(matrix.ncols(), 2);
+        assert_eq!(matrix.nnz(), 0);
+        assert_eq!(matrix.row_offsets(), &[0, 0, 0, 0]);
+        assert_eq!(matrix.col_indices(), &[]);
+        assert_eq!(matrix.values(), &[]);
+
+        assert!(matrix.triplet_iter().next().is_none());
+        assert!(matrix.triplet_iter_mut().next().is_none());
+
+        assert_eq!(matrix.row(0).ncols(), 2);
+        assert_eq!(matrix.row(0).nnz(), 0);
+        assert_eq!(matrix.row(0).col_indices(), &[]);
+        assert_eq!(matrix.row(0).values(), &[]);
+        assert_eq!(matrix.row_mut(0).ncols(), 2);
+        assert_eq!(matrix.row_mut(0).nnz(), 0);
+        assert_eq!(matrix.row_mut(0).col_indices(), &[]);
+        assert_eq!(matrix.row_mut(0).values(), &[]);
+        assert_eq!(matrix.row_mut(0).values_mut(), &[]);
+        assert_eq!(matrix.row_mut(0).cols_and_values_mut(), ([].as_ref(), [].as_mut()));
+
+        assert_eq!(matrix.row(1).ncols(), 2);
+        assert_eq!(matrix.row(1).nnz(), 0);
+        assert_eq!(matrix.row(1).col_indices(), &[]);
+        assert_eq!(matrix.row(1).values(), &[]);
+        assert_eq!(matrix.row_mut(1).ncols(), 2);
+        assert_eq!(matrix.row_mut(1).nnz(), 0);
+        assert_eq!(matrix.row_mut(1).col_indices(), &[]);
+        assert_eq!(matrix.row_mut(1).values(), &[]);
+        assert_eq!(matrix.row_mut(1).values_mut(), &[]);
+        assert_eq!(matrix.row_mut(1).cols_and_values_mut(), ([].as_ref(), [].as_mut()));
+
+        assert_eq!(matrix.row(2).ncols(), 2);
+        assert_eq!(matrix.row(2).nnz(), 0);
+        assert_eq!(matrix.row(2).col_indices(), &[]);
+        assert_eq!(matrix.row(2).values(), &[]);
+        assert_eq!(matrix.row_mut(2).ncols(), 2);
+        assert_eq!(matrix.row_mut(2).nnz(), 0);
+        assert_eq!(matrix.row_mut(2).col_indices(), &[]);
+        assert_eq!(matrix.row_mut(2).values(), &[]);
+        assert_eq!(matrix.row_mut(2).values_mut(), &[]);
+        assert_eq!(matrix.row_mut(2).cols_and_values_mut(), ([].as_ref(), [].as_mut()));
+
+        assert!(matrix.get_row(3).is_none());
+        assert!(matrix.get_row_mut(3).is_none());
+
+        let (offsets, indices, values) = matrix.disassemble();
+
+        assert_eq!(offsets, vec![0, 0, 0, 0]);
+        assert_eq!(indices, vec![]);
+        assert_eq!(values, vec![]);
+    }
+
+    {
+        // An arbitrary CSR matrix
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 5, 1, 2, 3];
+        let values = vec![0, 1, 2, 3, 4];
+        let mut matrix = CsrMatrix::try_from_csr_data(3,
+                                                      6,
+                                                      offsets.clone(),
+                                                      indices.clone(),
+                                                      values.clone()).unwrap();
+
+        assert_eq!(matrix.nrows(), 3);
+        assert_eq!(matrix.ncols(), 6);
+        assert_eq!(matrix.nnz(), 5);
+        assert_eq!(matrix.row_offsets(), &[0, 2, 2, 5]);
+        assert_eq!(matrix.col_indices(), &[0, 5, 1, 2, 3]);
+        assert_eq!(matrix.values(), &[0, 1, 2, 3, 4]);
+
+        let expected_triplets = vec![(0, 0, 0), (0, 5, 1), (2, 1, 2), (2, 2, 3), (2, 3, 4)];
+        assert_eq!(matrix.triplet_iter().map(|(i, j, v)| (i, j, *v)).collect::<Vec<_>>(),
+                   expected_triplets);
+        assert_eq!(matrix.triplet_iter_mut().map(|(i, j, v)| (i, j, *v)).collect::<Vec<_>>(),
+                   expected_triplets);
+
+        assert_eq!(matrix.row(0).ncols(), 6);
+        assert_eq!(matrix.row(0).nnz(), 2);
+        assert_eq!(matrix.row(0).col_indices(), &[0, 5]);
+        assert_eq!(matrix.row(0).values(), &[0, 1]);
+        assert_eq!(matrix.row_mut(0).ncols(), 6);
+        assert_eq!(matrix.row_mut(0).nnz(), 2);
+        assert_eq!(matrix.row_mut(0).col_indices(), &[0, 5]);
+        assert_eq!(matrix.row_mut(0).values(), &[0, 1]);
+        assert_eq!(matrix.row_mut(0).values_mut(), &[0, 1]);
+        assert_eq!(matrix.row_mut(0).cols_and_values_mut(), ([0, 5].as_ref(), [0, 1].as_mut()));
+
+        assert_eq!(matrix.row(1).ncols(), 6);
+        assert_eq!(matrix.row(1).nnz(), 0);
+        assert_eq!(matrix.row(1).col_indices(), &[]);
+        assert_eq!(matrix.row(1).values(), &[]);
+        assert_eq!(matrix.row_mut(1).ncols(), 6);
+        assert_eq!(matrix.row_mut(1).nnz(), 0);
+        assert_eq!(matrix.row_mut(1).col_indices(), &[]);
+        assert_eq!(matrix.row_mut(1).values(), &[]);
+        assert_eq!(matrix.row_mut(1).values_mut(), &[]);
+        assert_eq!(matrix.row_mut(1).cols_and_values_mut(), ([].as_ref(), [].as_mut()));
+
+        assert_eq!(matrix.row(2).ncols(), 6);
+        assert_eq!(matrix.row(2).nnz(), 3);
+        assert_eq!(matrix.row(2).col_indices(), &[1, 2, 3]);
+        assert_eq!(matrix.row(2).values(), &[2, 3, 4]);
+        assert_eq!(matrix.row_mut(2).ncols(), 6);
+        assert_eq!(matrix.row_mut(2).nnz(), 3);
+        assert_eq!(matrix.row_mut(2).col_indices(), &[1, 2, 3]);
+        assert_eq!(matrix.row_mut(2).values(), &[2, 3, 4]);
+        assert_eq!(matrix.row_mut(2).values_mut(), &[2, 3, 4]);
+        assert_eq!(matrix.row_mut(2).cols_and_values_mut(), ([1, 2, 3].as_ref(), [2, 3, 4].as_mut()));
+
+        assert!(matrix.get_row(3).is_none());
+        assert!(matrix.get_row_mut(3).is_none());
+
+        let (offsets2, indices2, values2) = matrix.disassemble();
+
+        assert_eq!(offsets2, offsets);
+        assert_eq!(indices2, indices);
+        assert_eq!(values2, values);
+    }
+}
+
+#[test]
+fn csr_matrix_try_from_invalid_csr_data() {
+
+    {
+        // Empty offset array (invalid length)
+        let matrix = CsrMatrix::try_from_csr_data(0, 0, Vec::new(), Vec::new(), Vec::<u32>::new());
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::InvalidStructure);
+    }
+
+    {
+        // Offset array invalid length for arbitrary data
+        let offsets = vec![0, 3, 5];
+        let indices = vec![0, 1, 2, 3, 5];
+        let values = vec![0, 1, 2, 3, 4];
+
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::InvalidStructure);
+    }
+
+    {
+        // Invalid first entry in offsets array
+        let offsets = vec![1, 2, 2, 5];
+        let indices = vec![0, 5, 1, 2, 3];
+        let values = vec![0, 1, 2, 3, 4];
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::InvalidStructure);
+    }
+
+    {
+        // Invalid last entry in offsets array
+        let offsets = vec![0, 2, 2, 4];
+        let indices = vec![0, 5, 1, 2, 3];
+        let values = vec![0, 1, 2, 3, 4];
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::InvalidStructure);
+    }
+
+    {
+        // Invalid length of offsets array
+        let offsets = vec![0, 2, 2];
+        let indices = vec![0, 5, 1, 2, 3];
+        let values = vec![0, 1, 2, 3, 4];
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::InvalidStructure);
+    }
+
+    {
+        // Nonmonotonic offsets
+        let offsets = vec![0, 3, 2, 5];
+        let indices = vec![0, 1, 2, 3, 4];
+        let values = vec![0, 1, 2, 3, 4];
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::InvalidStructure);
+    }
+
+    {
+        // Nonmonotonic minor indices
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 2, 3, 1, 4];
+        let values = vec![0, 1, 2, 3, 4];
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::InvalidStructure);
+    }
+
+    {
+        // Minor index out of bounds
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 6, 1, 2, 3];
+        let values = vec![0, 1, 2, 3, 4];
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::IndexOutOfBounds);
+    }
+
+    {
+        // Duplicate entry
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 5, 2, 2, 3];
+        let values = vec![0, 1, 2, 3, 4];
+        let matrix = CsrMatrix::try_from_csr_data(3, 6, offsets, indices, values);
+        assert_eq!(matrix.unwrap_err().kind(), &SparseFormatErrorKind::DuplicateEntry);
+    }
+
+}
+
+#[test]
+fn csr_matrix_get_index() {
+    // TODO: Implement tests for ::get() and index()
+}
+
+#[test]
+fn csr_matrix_row_iter() {
+
+}
\ No newline at end of file
diff --git a/nalgebra-sparse/tests/unit_tests/mod.rs b/nalgebra-sparse/tests/unit_tests/mod.rs
index 0c1631c4..2db7ab12 100644
--- a/nalgebra-sparse/tests/unit_tests/mod.rs
+++ b/nalgebra-sparse/tests/unit_tests/mod.rs
@@ -1,2 +1,4 @@
 mod coo;
-mod ops;
\ No newline at end of file
+mod ops;
+mod pattern;
+mod csr;
\ No newline at end of file
diff --git a/nalgebra-sparse/tests/unit_tests/pattern.rs b/nalgebra-sparse/tests/unit_tests/pattern.rs
new file mode 100644
index 00000000..4664ad74
--- /dev/null
+++ b/nalgebra-sparse/tests/unit_tests/pattern.rs
@@ -0,0 +1,130 @@
+use nalgebra_sparse::pattern::{SparsityPattern, SparsityPatternFormatError};
+
+#[test]
+fn sparsity_pattern_valid_data() {
+    // Construct pattern from valid data and check that selected methods return results
+    // that agree with expectations.
+
+    {
+        // A pattern with zero explicitly stored entries
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3,
+                                                                    2,
+                                                                    vec![0, 0, 0, 0],
+                                                                    Vec::new())
+            .unwrap();
+
+        assert_eq!(pattern.major_dim(), 3);
+        assert_eq!(pattern.minor_dim(), 2);
+        assert_eq!(pattern.nnz(), 0);
+        assert_eq!(pattern.major_offsets(), &[0, 0, 0, 0]);
+        assert_eq!(pattern.minor_indices(), &[]);
+        assert_eq!(pattern.lane(0), &[]);
+        assert_eq!(pattern.lane(1), &[]);
+        assert_eq!(pattern.lane(2), &[]);
+        assert!(pattern.entries().next().is_none());
+
+        assert_eq!(pattern, SparsityPattern::new(3, 2));
+
+        let (offsets, indices) = pattern.disassemble();
+        assert_eq!(offsets, vec![0, 0, 0, 0]);
+        assert_eq!(indices, vec![]);
+    }
+
+    {
+        // Arbitrary pattern
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 5, 1, 2, 3];
+        let pattern =
+            SparsityPattern::try_from_offsets_and_indices(3, 6, offsets.clone(), indices.clone())
+            .unwrap();
+
+        assert_eq!(pattern.major_dim(), 3);
+        assert_eq!(pattern.minor_dim(), 6);
+        assert_eq!(pattern.major_offsets(), offsets.as_slice());
+        assert_eq!(pattern.minor_indices(), indices.as_slice());
+        assert_eq!(pattern.nnz(), 5);
+        assert_eq!(pattern.lane(0), &[0, 5]);
+        assert_eq!(pattern.lane(1), &[]);
+        assert_eq!(pattern.lane(2), &[1, 2, 3]);
+        assert_eq!(pattern.entries().collect::<Vec<_>>(),
+                   vec![(0, 0), (0, 5), (2, 1), (2, 2), (2, 3)]);
+
+        let (offsets2, indices2) = pattern.disassemble();
+        assert_eq!(offsets2, offsets);
+        assert_eq!(indices2, indices);
+    }
+}
+
+#[test]
+fn sparsity_pattern_try_from_invalid_data() {
+    {
+        // Empty offset array (invalid length)
+        let pattern = SparsityPattern::try_from_offsets_and_indices(0, 0, Vec::new(), Vec::new());
+        assert_eq!(pattern, Err(SparsityPatternFormatError::InvalidOffsetArrayLength));
+    }
+
+    {
+        // Offset array invalid length for arbitrary data
+        let offsets = vec![0, 3, 5];
+        let indices = vec![0, 1, 2, 3, 5];
+
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert!(matches!(pattern, Err(SparsityPatternFormatError::InvalidOffsetArrayLength)));
+    }
+
+    {
+        // Invalid first entry in offsets array
+        let offsets = vec![1, 2, 2, 5];
+        let indices = vec![0, 5, 1, 2, 3];
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert!(matches!(pattern, Err(SparsityPatternFormatError::InvalidOffsetFirstLast)));
+    }
+
+    {
+        // Invalid last entry in offsets array
+        let offsets = vec![0, 2, 2, 4];
+        let indices = vec![0, 5, 1, 2, 3];
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert!(matches!(pattern, Err(SparsityPatternFormatError::InvalidOffsetFirstLast)));
+    }
+
+    {
+        // Invalid length of offsets array
+        let offsets = vec![0, 2, 2];
+        let indices = vec![0, 5, 1, 2, 3];
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert!(matches!(pattern, Err(SparsityPatternFormatError::InvalidOffsetArrayLength)));
+    }
+
+    {
+        // Nonmonotonic offsets
+        let offsets = vec![0, 3, 2, 5];
+        let indices = vec![0, 1, 2, 3, 4];
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert_eq!(pattern, Err(SparsityPatternFormatError::NonmonotonicOffsets));
+    }
+
+    {
+        // Nonmonotonic minor indices
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 2, 3, 1, 4];
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert_eq!(pattern, Err(SparsityPatternFormatError::NonmonotonicMinorIndices));
+    }
+
+    {
+        // Minor index out of bounds
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 6, 1, 2, 3];
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert_eq!(pattern, Err(SparsityPatternFormatError::MinorIndexOutOfBounds));
+    }
+
+    {
+        // Duplicate entry
+        let offsets = vec![0, 2, 2, 5];
+        let indices = vec![0, 5, 2, 2, 3];
+        let pattern = SparsityPattern::try_from_offsets_and_indices(3, 6, offsets, indices);
+        assert_eq!(pattern, Err(SparsityPatternFormatError::DuplicateEntry));
+    }
+}
\ No newline at end of file