Add set difference function

1 files changed, 7 insertions, 0 deletions

diff --git a/test/gleam/set_test.gleam b/test/gleam/set_test.gleam
index 85eaf4b..06af5dc 100644
--- a/test/gleam/set_test.gleam
+++ b/test/gleam/set_test.gleam
@@ -63,6 +63,7 @@ pub fn fold_test() {
   [1, 3, 9]
   |> set.from_list
   |> set.fold(from: 0, with: fn(m, a) { m + a })
+  |> should.equal(13)
 }
 
 pub fn filter_test() {
@@ -100,3 +101,9 @@ pub fn intersection_test() {
   |> set.to_list
   |> should.equal([2])
 }
+
+pub fn difference_test() {
+  set.difference(set.from_list([1, 2]), set.from_list([2, 3, 4]))
+  |> set.to_list
+  |> should.equal([1])
+}