nalgebra-sparse: Move slow tests and imports into 'slow' child module

This way it's easier to prevent accidental unused imports when
running tests without the slow-tests feature.

nalgebra-sparse/tests/unit_tests/proptest.rs

@@ -1,25 +1,29 @@
-use nalgebra_sparse::proptest::{coo_with_duplicates, coo_no_duplicates};
-use nalgebra::DMatrix;
-
-use proptest::prelude::*;
-use itertools::Itertools;
-
-use std::collections::HashSet;
-use std::iter::repeat;
+#[test]
+#[ignore]
+fn coo_no_duplicates_generates_admissible_matrices() {
+    //TODO
+}
 
 #[cfg(feature = "slow-tests")]
-use {
-    proptest::test_runner::TestRunner,
-    proptest::strategy::ValueTree
-};
-use std::ops::RangeInclusive;
+mod slow {
+    use nalgebra_sparse::proptest::{coo_with_duplicates, coo_no_duplicates};
+    use nalgebra::DMatrix;
 
-#[cfg(feature = "slow-tests")]
-fn generate_all_possible_matrices(value_range: RangeInclusive<i32>,
+    use proptest::test_runner::TestRunner;
+    use proptest::strategy::ValueTree;
+    use itertools::Itertools;
+
+    use proptest::prelude::*;
+
+    use std::collections::HashSet;
+    use std::iter::repeat;
+    use std::ops::RangeInclusive;
+
+    fn generate_all_possible_matrices(value_range: RangeInclusive<i32>,
                                       rows_range: RangeInclusive<usize>,
                                       cols_range: RangeInclusive<usize>)
                                       -> HashSet<DMatrix<i32>>
-{
+    {
         // Enumerate all possible combinations
         let mut all_combinations = HashSet::new();
         for nrows in rows_range {
@@ -49,11 +53,11 @@ fn generate_all_possible_matrices(value_range: RangeInclusive<i32>,
             }
         }
         all_combinations
-}
+    }
 
-#[cfg(feature = "slow-tests")]
-#[test]
-fn coo_no_duplicates_samples_all_admissible_outputs() {
+    #[cfg(feature = "slow-tests")]
+    #[test]
+    fn coo_no_duplicates_samples_all_admissible_outputs() {
         // Note: This test basically mirrors a similar test for `matrix` in the `nalgebra` repo.
 
         // Test that the proptest generation covers all possible outputs for a small space of inputs
@@ -85,11 +89,11 @@ fn coo_no_duplicates_samples_all_admissible_outputs() {
 
         assert_eq!(visited_combinations.len(), all_combinations.len());
         assert_eq!(visited_combinations, all_combinations, "Did not sample all possible values.");
-}
+    }
 
-#[cfg(feature = "slow-tests")]
-#[test]
-fn coo_with_duplicates_samples_all_admissible_outputs() {
+    #[cfg(feature = "slow-tests")]
+    #[test]
+    fn coo_with_duplicates_samples_all_admissible_outputs() {
         // This is almost the same as the test for coo_no_duplicates, except that we need
         // a different "success" criterion, since coo_with_duplicates is able to generate
         // matrices with values outside of the value constraints. See below for details.
@@ -126,9 +130,5 @@ fn coo_with_duplicates_samples_all_admissible_outputs() {
         // In other words, we need to determine that set of all admissible matrices
         // is contained in the set of visited matrices
         assert!(all_combinations.is_subset(&visited_combinations));
-}
-
-#[test]
-fn coo_no_duplicates_generates_admissible_matrices() {
-
+    }
 }