Queue data type

1 files changed, 227 insertions, 0 deletions

diff --git a/test/gleam/queue_test.gleam b/test/gleam/queue_test.gleam
new file mode 100644
index 0000000..128dab0
--- /dev/null
+++ b/test/gleam/queue_test.gleam
@@ -0,0 +1,227 @@
+import gleam/queue
+import gleam/int
+import gleam/list
+import gleam/should
+
+pub fn from_and_to_list_test() {
+  queue.from_list([])
+  |> should.equal(queue.new())
+
+  let test = fn(input) {
+    queue.from_list(input)
+    |> queue.to_list
+    |> should.equal(input)
+  }
+
+  test([])
+  test([1])
+  test([1, 2])
+  test([1, 2, 1])
+  test([1, 2, 1, 5, 2, 7, 2, 7, 8, 4, 545])
+}
+
+pub fn is_empty_test() {
+  queue.new()
+  |> queue.is_empty
+  |> should.be_true
+
+  queue.from_list([""])
+  |> queue.is_empty
+  |> should.be_false
+}
+
+pub fn length_test() {
+  let test = fn(input) {
+    queue.from_list(input)
+    |> queue.length
+    |> should.equal(list.length(input))
+  }
+
+  test([])
+  test([1])
+  test([1, 2])
+  test([1, 2, 1])
+  test([1, 2, 1, 5, 2, 7, 2, 7, 8, 4, 545])
+}
+
+pub fn push_test() {
+  queue.new()
+  |> queue.push_back(7)
+  |> queue.push_back(8)
+  |> queue.push_back(2)
+  |> queue.to_list
+  |> should.equal([2, 8, 7])
+}
+
+pub fn push_front_test() {
+  queue.new()
+  |> queue.push_back(7)
+  |> queue.push_back(8)
+  |> queue.push_back(2)
+  |> queue.push_front(4)
+  |> queue.push_front(3)
+  |> queue.to_list
+  |> should.equal([2, 8, 7, 4, 3])
+}
+
+pub fn pop_back_test() {
+  // We cannot construct the expected remainaing queue with from_list because
+  // it has different internal representation.
+  let expected_rest = queue.new()
+    |> queue.push_front(1)
+    |> queue.push_front(2)
+  queue.from_list([1, 2, 3])
+  |> queue.pop_back
+  |> should.equal(Ok(tuple(3, expected_rest)))
+
+  queue.from_list([])
+  |> queue.pop_back
+  |> should.equal(Error(Nil))
+}
+
+pub fn pop_front_test() {
+  queue.from_list([1, 2, 3])
+  |> queue.pop_front
+  |> should.equal(Ok(tuple(1, queue.from_list([2, 3]))))
+
+  queue.from_list([])
+  |> queue.pop_front
+  |> should.equal(Error(Nil))
+}
+
+pub fn reverse_test() {
+  queue.from_list([1, 2, 3])
+  |> queue.reverse
+  |> queue.to_list
+  |> should.equal([3, 2, 1])
+}
+
+pub fn is_equal_test() {
+  let should_equal = fn(a, b) {
+    a
+    |> queue.is_equal(to: b)
+    |> should.be_true
+  }
+
+  let should_not_equal = fn(a, b) {
+    a
+    |> queue.is_equal(to: b)
+    |> should.be_false
+  }
+
+  should_equal(queue.new(), queue.new())
+
+  queue.new()
+  |> queue.push_front(1)
+  |> should_equal(
+    queue.new()
+    |> queue.push_back(1),
+  )
+
+  queue.new()
+  |> queue.push_front(1)
+  |> should_equal(
+    queue.new()
+    |> queue.push_front(1),
+  )
+
+  queue.new()
+  |> queue.push_back(1)
+  |> queue.push_back(2)
+  |> should_equal(
+    queue.new()
+    |> queue.push_front(2)
+    |> queue.push_front(1),
+  )
+
+  queue.new()
+  |> queue.push_back(1)
+  |> should_not_equal(
+    queue.new()
+    |> queue.push_front(2)
+    |> queue.push_front(1),
+  )
+
+  queue.new()
+  |> queue.push_back(2)
+  |> queue.push_back(1)
+  |> should_not_equal(
+    queue.new()
+    |> queue.push_front(2)
+    |> queue.push_front(1),
+  )
+}
+
+pub fn is_logically_equal_test() {
+  let both_even_or_odd = fn(a, b) { int.is_even(a) == int.is_even(b) }
+
+  let should_equal = fn(a, b) {
+    a
+    |> queue.is_logically_equal(to: b, checking: both_even_or_odd)
+    |> should.be_true
+  }
+
+  let should_not_equal = fn(a, b) {
+    a
+    |> queue.is_logically_equal(to: b, checking: both_even_or_odd)
+    |> should.be_false
+  }
+
+  should_equal(queue.new(), queue.new())
+
+  queue.new()
+  |> queue.push_front(3)
+  |> should_equal(
+    queue.new()
+    |> queue.push_back(1),
+  )
+
+  queue.new()
+  |> queue.push_front(4)
+  |> should_equal(
+    queue.new()
+    |> queue.push_back(2),
+  )
+
+  queue.new()
+  |> queue.push_front(3)
+  |> should_equal(
+    queue.new()
+    |> queue.push_front(1),
+  )
+
+  queue.new()
+  |> queue.push_back(3)
+  |> queue.push_back(4)
+  |> should_equal(
+    queue.new()
+    |> queue.push_front(2)
+    |> queue.push_front(1),
+  )
+
+  queue.new()
+  |> queue.push_back(1)
+  |> should_not_equal(
+    queue.new()
+    |> queue.push_front(2)
+    |> queue.push_front(1),
+  )
+
+  queue.new()
+  |> queue.push_back(2)
+  |> queue.push_back(1)
+  |> should_not_equal(
+    queue.new()
+    |> queue.push_front(2)
+    |> queue.push_front(1),
+  )
+
+  queue.new()
+  |> queue.push_back(4)
+  |> queue.push_back(3)
+  |> should_not_equal(
+    queue.new()
+    |> queue.push_front(2)
+    |> queue.push_front(1),
+  )
+}