added basic integration tests for .flatten_ok() without size_hint tests

Author: vadixidav

tests/flatten_ok.rs

@@ -0,0 +1,76 @@
+use itertools::{assert_equal, Itertools};
+use std::{ops::Range, vec::IntoIter};
+
+fn mix_data() -> IntoIter<Result<Range<i32>, bool>> {
+    vec![Ok(0..2), Err(false), Ok(2..4), Err(true), Ok(4..6)].into_iter()
+}
+
+fn ok_data() -> IntoIter<Result<Range<i32>, bool>> {
+    vec![Ok(0..2), Ok(2..4), Ok(4..6)].into_iter()
+}
+
+#[test]
+fn flatten_ok_mixed_expected_forward() {
+    assert_equal(
+        mix_data().flatten_ok(),
+        vec![
+            Ok(0),
+            Ok(1),
+            Err(false),
+            Ok(2),
+            Ok(3),
+            Err(true),
+            Ok(4),
+            Ok(5),
+        ],
+    );
+}
+
+#[test]
+fn flatten_ok_mixed_expected_reverse() {
+    assert_equal(
+        mix_data().flatten_ok().rev(),
+        vec![
+            Ok(5),
+            Ok(4),
+            Err(true),
+            Ok(3),
+            Ok(2),
+            Err(false),
+            Ok(1),
+            Ok(0),
+        ],
+    );
+}
+
+#[test]
+fn flatten_ok_collect_mixed_forward() {
+    assert_eq!(
+        mix_data().flatten_ok().collect::<Result<Vec<_>, _>>(),
+        Err(false)
+    );
+}
+
+#[test]
+fn flatten_ok_collect_mixed_reverse() {
+    assert_eq!(
+        mix_data().flatten_ok().rev().collect::<Result<Vec<_>, _>>(),
+        Err(true)
+    );
+}
+
+#[test]
+fn flatten_ok_collect_ok_forward() {
+    assert_eq!(
+        ok_data().flatten_ok().collect::<Result<Vec<_>, _>>(),
+        Ok((0..6).collect())
+    );
+}
+
+#[test]
+fn flatten_ok_collect_ok_reverse() {
+    assert_eq!(
+        ok_data().flatten_ok().rev().collect::<Result<Vec<_>, _>>(),
+        Ok((0..6).rev().collect())
+    );
+}