test: add PHPUnit infrastructure and unit tests for config and AI generator

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

tests/bootstrap.php

@@ -0,0 +1,114 @@
+<?php
+/**
+ * PHPUnit bootstrap file for Peptide Search AI tests.
+ *
+ * Initializes the test environment with minimal WordPress stubs.
+ *
+ * @package PeptideSearchAI
+ */
+
+// Define WordPress constants.
+define( 'ABSPATH', __DIR__ . '/../' );
+define( 'PSA_PLUGIN_DIR', ABSPATH );
+define( 'PSA_PLUGIN_FILE', ABSPATH . 'peptide-search-ai.php' );
+define( 'PSA_VERSION', '1.0.0' );
+
+// Stub WordPress functions.
+if ( ! function_exists( 'sanitize_text_field' ) ) {
+	function sanitize_text_field( $str ) {
+		return $str;
+	}
+}
+
+if ( ! function_exists( 'wp_json_encode' ) ) {
+	function wp_json_encode( $data, $options = 0, $depth = 512 ) {
+		return json_encode( $data, $options, $depth );
+	}
+}
+
+if ( ! function_exists( 'get_option' ) ) {
+	function get_option( $option, $default = false ) {
+		return array();
+	}
+}
+
+if ( ! function_exists( 'get_transient' ) ) {
+	function get_transient( $transient ) {
+		return false;
+	}
+}
+
+if ( ! function_exists( 'set_transient' ) ) {
+	function set_transient( $transient, $value, $expiration = 0 ) {
+		return true;
+	}
+}
+
+if ( ! function_exists( 'wp_unslash' ) ) {
+	function wp_unslash( $value ) {
+		return $value;
+	}
+}
+
+if ( ! function_exists( 'apply_filters' ) ) {
+	function apply_filters( $hook, $value ) {
+		// Return the first non-hook argument (typically the second arg onwards)
+		$args = func_get_args();
+		return isset( $args[1] ) ? $args[1] : $value;
+	}
+}
+
+if ( ! function_exists( 'is_wp_error' ) ) {
+	function is_wp_error( $thing ) {
+		return class_exists( 'WP_Error' ) && $thing instanceof WP_Error;
+	}
+}
+
+if ( ! function_exists( 'wp_kses_post' ) ) {
+	function wp_kses_post( $data ) {
+		return $data;
+	}
+}
+
+// Define WP_Error class if it doesn't exist.
+if ( ! class_exists( 'WP_Error' ) ) {
+	class WP_Error {
+		public $errors = array();
+		public $error_data = array();
+
+		public function __construct( $code = '', $message = '', $data = '' ) {
+			if ( ! empty( $code ) ) {
+				$this->add( $code, $message, $data );
+			}
+		}
+
+		public function add( $code, $message = '', $data = '' ) {
+			if ( empty( $code ) ) {
+				return;
+			}
+			if ( ! isset( $this->errors[ $code ] ) ) {
+				$this->errors[ $code ] = array();
+			}
+			$this->errors[ $code ][] = $message;
+			if ( ! empty( $data ) ) {
+				$this->error_data[ $code ] = $data;
+			}
+		}
+
+		public function get_error_code() {
+			$codes = array_keys( $this->errors );
+			return ! empty( $codes ) ? $codes[0] : '';
+		}
+
+		public function get_error_message( $code = '' ) {
+			if ( empty( $code ) ) {
+				$code = $this->get_error_code();
+			}
+			return isset( $this->errors[ $code ][0] ) ? $this->errors[ $code ][0] : '';
+		}
+	}
+}
+
+// Require the class files under test.
+require_once ABSPATH . 'includes/class-psa-config.php';
+require_once ABSPATH . 'includes/class-psa-ai-generator.php';