Designate exhaustive matrix proptest as slow-tests

The slow-tests feature flag is intended to be used for tests
that take substantially more time to run than other unit tests.

.circleci/config.yml

@@ -57,10 +57,10 @@ jobs:
       - checkout
       - run:
           name: test
-          command: cargo test --features arbitrary --features serde-serialize --features abomonation-serialize --features sparse --features debug --features io --features compare --features libm --features proptest
+          command: cargo test --features arbitrary --features serde-serialize --features abomonation-serialize --features sparse --features debug --features io --features compare --features libm --features proptest --features slow-tests
       - run:
           name: test nalgebra-glm
-          command: cargo test -p nalgebra-glm  --features arbitrary --features serde-serialize --features abomonation-serialize --features sparse --features debug --features io --features compare --features libm
+          command: cargo test -p nalgebra-glm  --features arbitrary --features serde-serialize --features abomonation-serialize --features sparse --features debug --features io --features compare --features libm --features slow-tests
   build-wasm:
     executor: rust-executor
     steps:

Cargo.toml

@@ -34,6 +34,9 @@ compare = [ "matrixcompare-core" ]
 libm = [ "simba/libm" ]
 libm-force = [ "simba/libm_force" ]
 
+# This feature is only used for tests, and enables tests that require more time to run
+slow-tests = []
+
 
 [dependencies]
 typenum        = "1.12"

tests/proptest/mod.rs

@@ -5,9 +5,13 @@ use nalgebra::{DMatrix, DVector, Dim, Matrix3, MatrixMN, Vector3};
 use proptest::prelude::*;
 use proptest::strategy::ValueTree;
 use proptest::test_runner::TestRunner;
-use itertools::Itertools;
-use std::iter::repeat;
-use std::collections::HashSet;
+
+#[cfg(feature = "slow-tests")]
+use {
+    itertools::Itertools,
+    std::iter::repeat,
+    std::collections::HashSet,
+};
 
 /// Generate a proptest that tests that all matrices generated with the
 /// provided rows and columns conform to the constraints defined by the
@@ -92,6 +96,7 @@ proptest! {
     fn ensure_arbitrary_test_compiles_dvector(_: DVector<i32>) {}
 }
 
+#[cfg(feature = "slow-tests")]
 #[test]
 fn matrix_samples_all_possible_outputs() {
     // Test that the proptest generation covers all possible outputs for a small space of inputs