Add `assert` integration tests

test/assert/.gitignore

···
+build

test/assert/Makefile

···
+.PHONY: test-all
+test-all:
+	@echo test/assert
+	@./run_tests.sh

test/assert/gleam.toml

···
+name = "project"
+version = "1.0.0"
+description = "A Gleam project"
+
+[dependencies]
+gleam_stdlib = ">= 0.58.0 and < 2.0.0"

test/assert/manifest.toml

···
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "gleam_stdlib", version = "0.58.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "091F2D2C4A3A4E2047986C47E2C2C9D728A4E068ABB31FDA17B0D347E6248467" },
+]
+
+[requirements]
+gleam_stdlib = { version = ">= 0.58.0 and < 2.0.0" }

test/assert/run_tests.sh

···
+#/usr/bin/env sh
+
+set -eu
+
+should_succeed() {
+    echo
+    echo Running: "$@"
+
+    EXIT_CODE=0
+    cargo run -- $@ > /dev/null 2>&1 || EXIT_CODE=$?
+    if [ $EXIT_CODE -ne 0 ]
+    then
+        echo ERROR: Command should have succeeded
+        exit 1
+    else
+        echo Test Passed '(command run successfully)'
+    fi
+}
+
+should_fail() {
+    echo
+    echo Running: "$@"
+
+    EXIT_CODE=0
+    cargo run -- $@ > /dev/null 2>&1 || EXIT_CODE=$?
+
+    if [ $EXIT_CODE -eq 0 ]
+    then
+        echo ERROR: Command should have failed
+        exit 1
+    else
+        echo Test Passed '(command errored as expected)'
+    fi
+}
+
+all_targets() {
+  $@ --target erlang
+  $@ --target javascript --runtime nodejs
+  $@ --target javascript --runtime deno
+  $@ --target javascript --runtime bun
+}
+
+# Ensure the project builds correctly
+should_succeed build --target erlang
+should_succeed build --target javascript
+
+all_targets should_succeed run --module passing
+
+# Since a single failing `assert` will exit immediately, we must test each
+# failing case individually as separate modules.
+all_targets should_fail run --module failing1
+all_targets should_fail run --module failing2
+all_targets should_fail run --module failing3
+all_targets should_fail run --module failing4

test/assert/src/failing1.gleam

···
+pub fn main() {
+  let x = True
+  assert !x
+}

test/assert/src/failing2.gleam

···
+import gleam/int
+
+pub fn main() {
+  assert int.is_even(47)
+}

test/assert/src/failing3.gleam

···
+import gleam/bool
+import gleam/result
+
+pub fn main() {
+  assert bool.negate(False) && result.is_ok(Error(81))
+}

test/assert/src/failing4.gleam

···
+import gleam/int
+
+pub fn main() {
+  assert int.add(4, 5) > int.absolute_value(-11)
+}

test/assert/src/passing.gleam

···
+import gleam/bool
+import gleam/int
+import gleam/result
+
+/// All these assertions should succeed
+pub fn main() {
+  let x = True
+  assert x
+  assert case x && False {
+    True -> False
+    False -> True
+  }
+
+  assert result.is_ok(Ok(10))
+  assert result.is_error(Error("Hello"))
+
+  assert int.add(5, 6) == 11
+  assert int.add(1, 4) < 9
+  assert int.add(8, 12) >= 20
+  assert bool.negate(False) && result.is_ok(Ok(42))
+  assert int.is_even(3) || int.is_even(4)
+
+  // This should short-circuit so we don't panic here
+  assert True || panic
+}