Fix default overrides

See hallowelt/migrate-confluence#15

src/Builder.php

@@ -90,20 +90,14 @@ public function addRevision( $pagetitle, $wikitext, $timestamp = '', $username =
 			$this->pages[$pagetitle] = [];
 		}
 		$modelAndFormat = $this->getDefaultModelAndFormat( $pagetitle );
-		$defaults = [
-			'timestamp' => '',
-			'username' => '',
-			'model' => $modelAndFormat['model'],
-			'format' => $modelAndFormat['format']
-		];
 
-		$this->pages[$pagetitle][] = array_merge( [
+		$this->pages[$pagetitle][] = [
 			'text' => $wikitext,
 			'timestamp' => $timestamp,
 			'username' => $username,
-			'model' => $model,
-			'format' => $format
-		], $defaults );
+			'model' => empty( $model ) ? $modelAndFormat['model'] : $model,
+			'format' => empty( $format ) ? $modelAndFormat['format'] : $format
+		];
 
 		return $this;
 	}

tests/phpunit/BuilderTest.php

@@ -46,6 +46,12 @@ public function provideTestBuildAndSaveData() {
 					[ "Coffee & Tea", "raffiné" ]
 				],
 				__DIR__ . '/data/expected2.xml'
+			],
+			'explicit-model-and-format' => [
+				[
+					[ "Some.form", "...", '', '', 'form', 'text/x-form' ]
+				],
+				__DIR__ . '/data/expected3.xml'
 			]
 		];
 	}

tests/phpunit/data/expected3.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0"?>
+<mediawiki>
+  <page>
+    <title>Some.form</title>
+    <revision>
+      <model>form</model>
+      <format>text/x-form</format>
+      <text>...</text>
+    </revision>
+  </page>
+</mediawiki>