Added quickchecks

Author: Ten0

tests/specializations.rs

@@ -1,5 +1,8 @@
 extern crate itertools;
 
+#[macro_use]
+extern crate quickcheck;
+
 use itertools::{EitherOrBoth, Itertools};
 
 use std::fmt::Debug;
@@ -36,13 +39,17 @@ where
     )
 }
 
-fn check_specialized_count_last_nth_sizeh<'a, IterItem, Iter>(it: &Iter, expected_size: usize)
-where
+fn check_specialized_count_last_nth_sizeh<'a, IterItem, Iter>(
+    it: &Iter,
+    known_expected_size: Option<usize>,
+) where
     IterItem: 'a + Eq + Debug,
     Iter: Iterator<Item = IterItem> + Clone + 'a,
 {
     let size = it.clone().count();
-    assert_eq!(size, expected_size);
+    if let Some(expected_size) = known_expected_size {
+        assert_eq!(size, expected_size);
+    }
     check_specialized(it, |i| i.count());
     check_specialized(it, |i| i.last());
     for n in 0..size + 2 {
@@ -79,28 +86,36 @@ where
     });
 }
 
-#[test]
-fn put_back() {
-    let test_vec = vec![7, 4, 1];
+fn put_back_test(test_vec: Vec<i32>, known_expected_size: Option<usize>) {
     {
         // Lexical lifetimes support
         let pb = itertools::put_back(test_vec.iter());
-        check_specialized_count_last_nth_sizeh(&pb, 3);
+        check_specialized_count_last_nth_sizeh(&pb, known_expected_size);
         check_specialized_fold_xor(&pb);
     }
 
     let mut pb = itertools::put_back(test_vec.into_iter());
     pb.put_back(1);
-    check_specialized_count_last_nth_sizeh(&pb, 4);
-    check_specialized_fold_xor(&pb);
+    check_specialized_count_last_nth_sizeh(&pb, known_expected_size.map(|x| x + 1));
+    check_specialized_fold_xor(&pb)
 }
 
 #[test]
-fn merge_join_by() {
-    let i1 = vec![1, 3, 5, 7, 8, 9].into_iter();
-    let i2 = vec![0, 3, 4, 5].into_iter();
+fn put_back() {
+    put_back_test(vec![7, 4, 1], Some(3));
+}
+
+quickcheck! {
+    fn put_back_qc(test_vec: Vec<i32>) -> () {
+        put_back_test(test_vec, None)
+    }
+}
+
+fn merge_join_by_test(i1: Vec<usize>, i2: Vec<usize>, known_expected_size: Option<usize>) {
+    let i1 = i1.into_iter();
+    let i2 = i2.into_iter();
     let mjb = i1.clone().merge_join_by(i2.clone(), std::cmp::Ord::cmp);
-    check_specialized_count_last_nth_sizeh(&mjb, 8);
+    check_specialized_count_last_nth_sizeh(&mjb, known_expected_size);
     // Rust 1.24 compatibility:
     fn eob_left_z(eob: EitherOrBoth<usize, usize>) -> usize {
         eob.left().unwrap_or(0)
@@ -117,10 +132,23 @@ fn merge_join_by() {
     check_specialized_fold_xor(&mjb.clone().map(eob_right_z));
     check_specialized_fold_xor(&mjb.clone().map(eob_both_z));
 
-	// And the other way around
+    // And the other way around
     let mjb = i2.merge_join_by(i1, std::cmp::Ord::cmp);
-    check_specialized_count_last_nth_sizeh(&mjb, 8);
+    check_specialized_count_last_nth_sizeh(&mjb, known_expected_size);
     check_specialized_fold_xor(&mjb.clone().map(eob_left_z));
     check_specialized_fold_xor(&mjb.clone().map(eob_right_z));
     check_specialized_fold_xor(&mjb.clone().map(eob_both_z));
 }
+
+#[test]
+fn merge_join_by() {
+    let i1 = vec![1, 3, 5, 7, 8, 9];
+    let i2 = vec![0, 3, 4, 5];
+    merge_join_by_test(i1, i2, Some(8));
+}
+
+quickcheck! {
+    fn merge_join_by_qc(i1: Vec<usize>, i2: Vec<usize>) -> () {
+        merge_join_by_test(i1, i2, None)
+    }
+}