Add unit test suite: 54 tests across models, core, and providers

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/unit/BaseTestCase.php

@@ -0,0 +1,82 @@
+<?php
+/**
+ * Base test case for all PRAutoBlogger unit tests.
+ *
+ * Provides Brain\Monkey setup/teardown and common helpers
+ * for mocking WordPress functions used across the plugin.
+ *
+ * @package PRAutoBlogger\Tests
+ */
+
+namespace PRAutoBlogger\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Brain\Monkey;
+use Brain\Monkey\Functions;
+
+abstract class BaseTestCase extends TestCase {
+
+    /**
+     * Set up Brain\Monkey before each test.
+     */
+    protected function setUp(): void {
+        parent::setUp();
+        Monkey\setUp();
+
+        // Common WordPress function stubs used across many classes.
+        Functions\stubTranslationFunctions();
+        Functions\stubEscapeFunctions();
+    }
+
+    /**
+     * Tear down Brain\Monkey after each test.
+     */
+    protected function tearDown(): void {
+        Monkey\tearDown();
+        parent::tearDown();
+    }
+
+    /**
+     * Helper: stub get_option with a map of option_name => value.
+     *
+     * @param array $options Key-value pairs of option names and their return values.
+     */
+    protected function stub_get_option( array $options ): void {
+        Functions\when( 'get_option' )->alias(
+            function ( string $name, $default = false ) use ( $options ) {
+                return $options[ $name ] ?? $default;
+            }
+        );
+    }
+
+    /**
+     * Helper: stub current_time to return a fixed timestamp.
+     *
+     * @param string $time MySQL datetime string (Y-m-d H:i:s).
+     */
+    protected function stub_current_time( string $time ): void {
+        Functions\when( 'current_time' )->alias(
+            function ( $type ) use ( $time ) {
+                return 'mysql' === $type ? $time : strtotime( $time );
+            }
+        );
+    }
+
+    /**
+     * Helper: create a mock $wpdb with expectations.
+     *
+     * @return \PHPUnit\Framework\MockObject\MockObject
+     */
+    protected function create_mock_wpdb() {
+        $wpdb = $this->getMockBuilder( \stdClass::class )
+            ->addMethods( [ 'prepare', 'get_var', 'get_results', 'insert', 'query', 'get_row' ] )
+            ->getMock();
+
+        $wpdb->prefix         = 'wp_';
+        $wpdb->insert_id      = 0;
+        $wpdb->last_error     = '';
+        $wpdb->prab_cost_logs = 'wp_prab_cost_logs';
+
+        return $wpdb;
+    }
+}