1 files changed, 80 insertions, 0 deletions

diff --git a/rust/etl/tests/etl.rs b/rust/etl/tests/etl.rs
new file mode 100644
index 0000000..e8e1e01
--- /dev/null
+++ b/rust/etl/tests/etl.rs
@@ -0,0 +1,80 @@
+use std::collections::BTreeMap;
+
+#[test]
+fn test_transform_one_value() {
+    let input = input_from(&[(1, vec!['A'])]);
+
+    let expected = expected_from(&[('a', 1)]);
+
+    assert_eq!(expected, etl::transform(&input));
+}
+
+#[test]
+fn test_transform_more_values() {
+    let input = input_from(&[(1, vec!['A', 'E', 'I', 'O', 'U'])]);
+
+    let expected = expected_from(&[('a', 1), ('e', 1), ('i', 1), ('o', 1), ('u', 1)]);
+
+    assert_eq!(expected, etl::transform(&input));
+}
+
+#[test]
+fn test_more_keys() {
+    let input = input_from(&[(1, vec!['A', 'E']), (2, vec!['D', 'G'])]);
+
+    let expected = expected_from(&[('a', 1), ('e', 1), ('d', 2), ('g', 2)]);
+
+    assert_eq!(expected, etl::transform(&input));
+}
+
+#[test]
+fn test_full_dataset() {
+    let input = input_from(&[
+        (1, vec!['A', 'E', 'I', 'O', 'U', 'L', 'N', 'R', 'S', 'T']),
+        (2, vec!['D', 'G']),
+        (3, vec!['B', 'C', 'M', 'P']),
+        (4, vec!['F', 'H', 'V', 'W', 'Y']),
+        (5, vec!['K']),
+        (8, vec!['J', 'X']),
+        (10, vec!['Q', 'Z']),
+    ]);
+
+    let expected = expected_from(&[
+        ('a', 1),
+        ('b', 3),
+        ('c', 3),
+        ('d', 2),
+        ('e', 1),
+        ('f', 4),
+        ('g', 2),
+        ('h', 4),
+        ('i', 1),
+        ('j', 8),
+        ('k', 5),
+        ('l', 1),
+        ('m', 3),
+        ('n', 1),
+        ('o', 1),
+        ('p', 3),
+        ('q', 10),
+        ('r', 1),
+        ('s', 1),
+        ('t', 1),
+        ('u', 1),
+        ('v', 4),
+        ('w', 4),
+        ('x', 8),
+        ('y', 4),
+        ('z', 10),
+    ]);
+
+    assert_eq!(expected, etl::transform(&input));
+}
+
+fn input_from(v: &[(i32, Vec<char>)]) -> BTreeMap<i32, Vec<char>> {
+    v.iter().cloned().collect()
+}
+
+fn expected_from(v: &[(char, i32)]) -> BTreeMap<char, i32> {
+    v.iter().cloned().collect()
+}