Add expect.string_to_not_end_with (#13)

This PR implements the negated counterpart of the `string_to_end_with`
assertion.

---------

Co-authored-by: Marshall Bowers <[email protected]>

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Added `expect/string_to_not_start_with` for asserting that a string does not start with another string.
+- Added `expect/string_to_not_end_with` for asserting that a string does not end with another string.
 
 ## [0.4.0] - 2024-06-14
 

birdie_snapshots/expect_string_to_not_end_with_given_matching_string.accepted

@@ -0,0 +1,11 @@
+---
+version: 1.1.5
+title: expect/string_to_not_end_with given matching string
+---
+Expected "Ants in my Eyes Johnson" to not end with "son"
+
+- Expected
++ Received
+
+- son
++ Ants in my Eyes Johnson

src/startest/expect.gleam

@@ -208,6 +208,25 @@ pub fn string_to_end_with(actual: String, expected: String) -> Nil {
   }
 }
 
+/// Asserts that the given string does not end with the expected string.
+pub fn string_to_not_end_with(actual: String, expected: String) -> Nil {
+  case string.ends_with(actual, expected) {
+    False -> Nil
+    True ->
+      AssertionError(
+        string.concat([
+          "Expected ",
+          string.inspect(actual),
+          " to not end with ",
+          string.inspect(expected),
+        ]),
+        actual,
+        expected,
+      )
+      |> assertion_error.raise
+  }
+}
+
 /// Asserts that the given list contains the expected element.
 pub fn list_to_contain(actual: List(a), expected: a) -> Nil {
   case list.contains(actual, expected) {

test/startest/expect_test.gleam

@@ -271,6 +271,28 @@ pub fn string_to_end_with_tests() {
   ])
 }
 
+pub fn string_to_not_end_with_tests() {
+  describe("startest/expect", [
+    describe("string_to_not_end_with", [
+      describe("given a string that does not end with the expected pattern", [
+        it_passes(fn() {
+          "Purpose Robot"
+          |> expect.string_to_not_end_with("bottle")
+        }),
+      ]),
+      describe("given a string that ends with the expected pattern", [
+        it_fails_matching_snapshot(
+          "expect/string_to_not_end_with given matching string",
+          fn() {
+            "Ants in my Eyes Johnson"
+            |> expect.string_to_not_end_with("son")
+          },
+        ),
+      ]),
+    ]),
+  ])
+}
+
 pub fn list_to_contain_tests() {
   describe("startest/expect", [
     describe("list_to_contain", [