issue#104 skip unit tests that rely on external tools

tests/wiki_content_mask_test.php

@@ -28,7 +28,11 @@ class wiki_content_mask_test extends \advanced_testcase {
      * Tests executing the mask, including retaining the wiki links.
      */
     public function test_execute(): void {
-        global $DB;
+        global $CFG, $DB;
+
+        if (!file_exists("{$CFG->dirroot}/admin/tool/datamasking/version.php")) {
+            $this->markTestSkipped('This test uses tool_datamasking, which is not installed. Skipping.');
+        }
 
         $this->resetAfterTest();
 
@@ -47,7 +51,7 @@ public function test_execute(): void {
                 '<p>[[First page]]</p><p>[[Second page]]</p><p>[[IInd page]]</p>']);
 
         // Run full processing.
-        $table = new \tool_datamasking\table('ouwiki_versions');
+        $table = new tool_datamasking\table('ouwiki_versions');
         $table->add(new wiki_content_mask());
         $table->execute([], [], new \core\progress\none());
 
@@ -65,6 +69,11 @@ public function test_execute(): void {
      * Tests the get_affected_fields function.
      */
     public function test_get_affected_fields(): void {
+        global $CFG;
+
+        if (!file_exists("{$CFG->dirroot}/admin/tool/datamasking/version.php")) {
+            $this->markTestSkipped('This test uses tool_datamasking, which is not installed. Skipping.');
+        }
         $mask = new wiki_content_mask();
         $this->assertEquals(['xhtml'], $mask->get_affected_fields());
     }
@@ -73,6 +82,11 @@ public function test_get_affected_fields(): void {
      * Tests the description text.
      */
     public function test_get_description_text(): void {
+        global $CFG;
+
+        if (!file_exists("{$CFG->dirroot}/admin/tool/datamasking/version.php")) {
+            $this->markTestSkipped('This test uses tool_datamasking, which is not installed. Skipping.');
+        }
         $mask = new wiki_content_mask();
         $this->assertEquals('Replace with fake text of a similar length, retaining HTML tags and '.
                 '[[wiki page]] links', $mask->get_description_text());