Migrate tests to Pest (#8)

Reviewed-on: #8

tests/Unit/Mapper/ExistsMapperTest.php

@@ -0,0 +1,28 @@
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);
+
+use BitBadger\PDODocument\{Configuration, DocumentException, Mode};
+use BitBadger\PDODocument\Mapper\ExistsMapper;
+
+pest()->group('unit');
+
+afterEach(function () { Configuration::overrideMode(null); });
+
+describe('->map()', function () {
+    test('returns a boolean value from index 0 [PostgreSQL]', function () {
+        Configuration::overrideMode(Mode::PgSQL);
+        expect((new ExistsMapper())->map([false, 'nope']))->toBeFalse();
+    });
+    test('returns a number value as boolean from index 0 [SQLite]', function () {
+        Configuration::overrideMode(Mode::SQLite);
+        expect((new ExistsMapper())->map([1, 'yep']))->toBeTrue();
+    });
+    test('throws if mode is not set', function () {
+        expect(fn() => (new ExistsMapper())->map(['0']))->toThrow(DocumentException::class);
+    });
+});