fix: rename test module to tests

examples/acceptance_tests/016/lib/tests.ak

@@ -0,0 +1,19 @@
+use aiken/builtin
+
+pub fn slice(bytes: ByteArray, start: Int, end: Int) -> ByteArray {
+  builtin.slice_bytearray(start, end, bytes)
+}
+
+pub fn length(bytes: ByteArray) -> Int {
+  builtin.length_of_bytearray(bytes)
+}
+
+pub fn drop(bytes: ByteArray, n: Int) -> ByteArray {
+  slice(bytes, n, length(bytes) - n)
+}
+
+test drop_1() {
+  let x = #[1, 2, 3, 4, 5, 6, 7]
+  drop(x, 2) == #[3, 4, 5, 6, 7]
+}
+