Ensure PDO source can gracefully handle reading from a table with no data

Author: Jordan Hall

src/Objects/Sources/PDOSource.php

@@ -38,7 +38,7 @@ protected function getTableFields()
 
         $row = $stmt->fetch(PDO::FETCH_ASSOC);
 
-        $tableFields = array_keys($row);
+        $tableFields = is_array($row) ? array_keys($row) : [];
 
         return $tableFields;
     }

tests/Unit/Data/source.sqlite

@@ -165,4 +165,25 @@ public function testCountPages()
 
         $this->assertEquals(1, $source->countPages());
     }
+
+    private function createEmptyTableSource()
+    {
+        return new PDOSource(new PDO('sqlite:'.__DIR__.'/Data/source.sqlite'), 'empty_table');
+    }
+
+    public function testGetFieldsOnEmptyTable()
+    {
+        $source = $this->createEmptyTableSource();
+
+        $this->assertEquals([], $source->getFields());
+    }
+
+    public function testGetDataRowsOnEmptyTable()
+    {
+        $source = $this->createEmptyTableSource();
+
+        $dataRows = $source->getDataRows(1, ['thing1', 'thing2']);
+
+        $this->assertCount(0, $dataRows);
+    }
 }