1 files changed, 57 insertions, 0 deletions
diff --git a/v_windows/v/vlib/rand/util/util_test.v b/v_windows/v/vlib/rand/util/util_test.v
new file mode 100644
index 0000000..f92e70b
--- /dev/null
+++ b/v_windows/v/vlib/rand/util/util_test.v
@@ -0,0 +1,57 @@
+import rand
+import rand.util
+
+fn test_sample_nr() {
+	lengths := [1, 3, 4, 5, 6, 7]
+	a := ['one', 'two', 'three', 'four', 'five', 'six', 'seven']
+	for length in lengths {
+		b := util.sample_nr(a, length)
+		assert b.len == length
+		for element in b {
+			assert element in a
+			// make sure every element occurs once
+			mut count := 0
+			for e in b {
+				if e == element {
+					count++
+				}
+			}
+			assert count == 1
+		}
+	}
+}
+
+fn test_sample_r() {
+	k := 20
+	a := ['heads', 'tails']
+	b := util.sample_r(a, k)
+	assert b.len == k
+	for element in b {
+		assert element in a
+	}
+}
+
+fn test_shuffle() {
+	rand.seed([u32(1), 2]) // set seed to produce same results in order
+	a := [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+	mut b := a.clone()
+	mut c := a.clone()
+	util.shuffle(mut b, 0)
+	util.shuffle(mut c, 0)
+	assert b == [6, 4, 5, 1, 9, 2, 10, 3, 8, 7]
+	assert c == [1, 6, 5, 8, 7, 2, 10, 9, 3, 4]
+	// test shuffling a slice
+	mut d := a.clone()
+	util.shuffle(mut d[..5], 0)
+	assert d == [5, 2, 1, 3, 4, 6, 7, 8, 9, 10]
+	assert d[5..] == a[5..]
+	// test shuffling n items
+	mut e := a.clone()
+	util.shuffle(mut e, 5)
+	assert e[..5] == [10, 3, 1, 8, 4]
+	assert e[5..] == [6, 7, 5, 9, 2]
+	// test shuffling empty array
+	mut f := a[..0]
+	util.shuffle(mut f, 0)
+	assert f == []int{}
+}