From 2d8405e99e4088627580d32140dcd8cef383b6fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Mudr=C3=A1k?= <david@moodle.com>
Date: Tue, 5 Mar 2019 13:47:14 +0100
Subject: [PATCH] MDL-64994 analytics: Add a simple semantic version check
 method

This method is to be used for checking that a compatible version of the
moodlemlbackend package is installed on the server. The package is
expected to use the semantic versioning scheme (semver.org).
---
 lib/mlbackend/python/classes/processor.php    |  35 ++++
 lib/mlbackend/python/tests/processor_test.php | 183 ++++++++++++++++++
 2 files changed, 218 insertions(+)
 create mode 100644 lib/mlbackend/python/tests/processor_test.php

diff --git a/lib/mlbackend/python/classes/processor.php b/lib/mlbackend/python/classes/processor.php
index e74de28cef2..cda1173dcd8 100644
--- a/lib/mlbackend/python/classes/processor.php
+++ b/lib/mlbackend/python/classes/processor.php
@@ -395,4 +395,39 @@ class processor implements  \core_analytics\classifier, \core_analytics\regresso
         // This is not ideal, but there is no read access to moodle filesystem files.
         return $file->copy_content_to_temp('core_analytics');
     }
+
+    /**
+     * Check that the given package version can be used and return the error status.
+     *
+     * When evaluating the version, we assume the sematic versioning scheme as described at
+     * https://semver.org/.
+     *
+     * @param string $actual The actual Python package version
+     * @param string $required The required version of the package
+     * @return int -1 = actual version is too low, 1 = actual version too high, 0 = actual version is ok
+     */
+    public static function check_pip_package_version($actual, $required = self::REQUIRED_PIP_PACKAGE_VERSION) {
+
+        if (empty($actual)) {
+            return -1;
+        }
+
+        if (version_compare($actual, $required, '<')) {
+            return -1;
+        }
+
+        $parts = explode('.', $required);
+        $requiredapiver = reset($parts);
+
+        $parts = explode('.', $actual);
+        $actualapiver = reset($parts);
+
+        if ($requiredapiver > 0 || $actualapiver > 1) {
+            if (version_compare($actual, $requiredapiver + 1, '>=')) {
+                return 1;
+            }
+        }
+
+        return 0;
+    }
 }
diff --git a/lib/mlbackend/python/tests/processor_test.php b/lib/mlbackend/python/tests/processor_test.php
new file mode 100644
index 00000000000..e9ceb51b273
--- /dev/null
+++ b/lib/mlbackend/python/tests/processor_test.php
@@ -0,0 +1,183 @@
+<?php
+// This file is part of Moodle - https://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Provides the {@link mlbackend_python_processor_testcase} class.
+ *
+ * @package     mlbackend_python
+ * @category    test
+ * @copyright   2019 David Mudrák <david@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Unit tests for the {@link \mlbackend_python\processor} class.
+ *
+ * @copyright 2019 David Mudrák <david@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class mlbackend_python_processor_testcase extends advanced_testcase {
+
+    /**
+     * Test implementation of the {@link \mlbackend_python\processor::check_pip_package_version()} method.
+     *
+     * @dataProvider check_pip_package_versions
+     * @param string $actual A sample of the actual package version
+     * @param string $required A sample of the required package version
+     * @param int $result Expected value returned by the tested method
+     */
+    public function test_check_pip_package_version($actual, $required, $result) {
+        $this->assertSame($result, \mlbackend_python\processor::check_pip_package_version($actual, $required));
+    }
+
+    /**
+     * Check that the {@link \mlbackend_python\processor::check_pip_package_version()} can be called with single argument.
+     */
+    public function test_check_pip_package_version_default() {
+
+        $this->assertSame(-1, \mlbackend_python\processor::check_pip_package_version('0.0.1'));
+        $this->assertSame(0, \mlbackend_python\processor::check_pip_package_version(
+            \mlbackend_python\processor::REQUIRED_PIP_PACKAGE_VERSION));
+    }
+
+    /**
+     * Provides data samples for the {@link self::test_check_pip_package_version()}.
+     *
+     * @return array
+     */
+    public function check_pip_package_versions() {
+        return [
+            // Exact match.
+            [
+                '0.0.5',
+                '0.0.5',
+                0,
+            ],
+            [
+                '1.0.0',
+                '1.0.0',
+                0,
+            ],
+            // Actual version higher than required, yet still API compatible.
+            [
+                '1.0.3',
+                '1.0.1',
+                0,
+            ],
+            [
+                '2.1.3',
+                '2.0.0',
+                0,
+            ],
+            [
+                '1.1.5',
+                '1.1',
+                0,
+            ],
+            [
+                '2.0.3',
+                '2',
+                0,
+            ],
+            // Actual version not high enough to meet the requirements.
+            [
+                '0.0.5',
+                '1.0.0',
+                -1,
+            ],
+            [
+                '0.37.0',
+                '1.0.0',
+                -1,
+            ],
+            [
+                '0.0.5',
+                '0.37.0',
+                -1,
+            ],
+            [
+                '2.0.0',
+                '2.0.2',
+                -1,
+            ],
+            [
+                '2.7.0',
+                '3.0',
+                -1,
+            ],
+            [
+                '2.8.9-beta1',
+                '3.0',
+                -1,
+            ],
+            [
+                '1.1.0-rc1',
+                '1.1.0',
+                -1,
+            ],
+            // Actual version too high and no longer API compatible.
+            [
+                '2.0.0',
+                '1.0.0',
+                1,
+            ],
+            [
+                '3.1.5',
+                '2.0',
+                1,
+            ],
+            [
+                '3.0.0',
+                '1.0',
+                1,
+            ],
+            [
+                '2.0.0',
+                '0.0.5',
+                1,
+            ],
+            [
+                '3.0.2',
+                '0.37.0',
+                1,
+            ],
+            // Zero major version requirement is fulfilled with 1.x API (0.x are not considered stable APIs).
+            [
+                '1.0.0',
+                '0.0.5',
+                0,
+            ],
+            [
+                '1.8.6',
+                '0.37.0',
+                0,
+            ],
+            // Empty version is never good enough.
+            [
+                '',
+                '1.0.0',
+                -1,
+            ],
+            [
+                '0.0.0',
+                '0.37.0',
+                -1,
+            ],
+        ];
+    }
+}