Add `bit_size()` and `starts_with()` to `gleam/bit_array`

1 files changed, 80 insertions, 0 deletions

diff --git a/test/gleam/bit_array_test.gleam b/test/gleam/bit_array_test.gleam
index a563c15..555c61a 100644
--- a/test/gleam/bit_array_test.gleam
+++ b/test/gleam/bit_array_test.gleam
@@ -4,6 +4,37 @@ import gleam/result
 import gleam/should
 import gleam/string
 
+pub fn bit_size_test() {
+  bit_array.bit_size(<<>>)
+  |> should.equal(0)
+
+  bit_array.bit_size(<<0>>)
+  |> should.equal(8)
+
+  bit_array.bit_size(<<-1:32>>)
+  |> should.equal(32)
+
+  bit_array.bit_size(<<0:-8>>)
+  |> should.equal(0)
+}
+
+// This test is target specific since it's using non byte-aligned BitArrays
+// and those are not supported on the JavaScript target.
+@target(erlang)
+pub fn bit_size_erlang_only_test() {
+  bit_array.bit_size(<<0:1>>)
+  |> should.equal(1)
+
+  bit_array.bit_size(<<7:3>>)
+  |> should.equal(3)
+
+  bit_array.bit_size(<<-1:190>>)
+  |> should.equal(190)
+
+  bit_array.bit_size(<<0:-1>>)
+  |> should.equal(0)
+}
+
 pub fn byte_size_test() {
   bit_array.byte_size(bit_array.from_string("hello"))
   |> should.equal(5)
@@ -379,3 +410,52 @@ pub fn compare_different_sizes_test() {
   bit_array.compare(<<0:2>>, <<0:1>>)
   |> should.equal(order.Gt)
 }
+
+pub fn starts_with_test() {
+  bit_array.starts_with(<<>>, <<>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<0>>, <<>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<>>, <<0>>)
+  |> should.be_false
+
+  bit_array.starts_with(<<0, 1, 2>>, <<0>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<0, 1, 2>>, <<0, 1>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<0, 1, 2>>, <<0, 1, 2>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<0, 1, 2>>, <<0, 1, 2, 3>>)
+  |> should.be_false
+
+  bit_array.starts_with(<<0, 1, 2>>, <<1>>)
+  |> should.be_false
+}
+
+// This test is target specific since it's using non byte-aligned BitArrays
+// and those are not supported on the JavaScript target.
+@target(erlang)
+pub fn starts_with_erlang_only_test() {
+  bit_array.starts_with(<<1:1>>, <<1:1>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<1:1>>, <<>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<1:1>>, <<1:2>>)
+  |> should.be_false
+
+  bit_array.starts_with(<<-1:127>>, <<-1:33>>)
+  |> should.be_true
+
+  bit_array.starts_with(<<-1:127>>, <<-1:128>>)
+  |> should.be_false
+
+  bit_array.starts_with(<<0:127>>, <<1:127>>)
+  |> should.be_false
+}