Prevent fatal error when fetching rows without values

Author: stloyd

src/adapter/etl-adapter-google-sheet/tests/Flow/ETL/Adapter/GoogleSheet/Tests/Fixtures/batch-empty-rows.json

@@ -0,0 +1,26 @@
+{
+  "spreadsheetId": "eae3913a86de8d5ccfe841fd3c7ec50dba3902045232",
+  "valueRanges": [
+    {
+      "range": "Sheet!A1:C10",
+      "majorDimension": "ROWS",
+      "values": [
+        ["Header 1", "Header 2", "Header 3"],
+        ["A2", "B2", "C2"],
+        ["A3", "B3", "C3"],
+        ["A4", "B4", "C4"],
+        ["A5", "B5", "C5"],
+        ["A6", "B6", "C6"],
+        ["A7", "B7", "C7"],
+        ["A8", "B8", "C8"],
+        ["A9", "B9", "C9"],
+        ["A10", "B10", "C10"]
+      ]
+    },
+    {
+      "range": "Sheet!A11:C20",
+      "majorDimension": "ROWS",
+      "values": null
+    }
+  ]
+}

src/adapter/etl-adapter-google-sheet/tests/Flow/ETL/Adapter/GoogleSheet/Tests/Integration/GoogleSheetExtractorTest.php

@@ -100,6 +100,23 @@ public function test_extract_with_batches() : void
         self::assertCount(19, $rows);
     }
 
+    public function test_extract_with_batches_containing_empty_rows() : void
+    {
+        $extractor = from_google_sheet(
+            $this->context->sheets(__DIR__ . '/../Fixtures/batch-empty-rows.json'),
+            '1234567890',
+            'Sheet',
+        );
+        $extractor->withRowsPerPage(10);
+
+        $rows = df()
+            ->extract($extractor)
+            ->fetch()
+            ->toArray();
+
+        self::assertCount(9, $rows);
+    }
+
     public function test_extract_with_batches_without_header() : void
     {
         $extractor = from_google_sheet(