diff --git a/src/ChangesReporting/Output/Factory/JsonOutputFactory.php b/src/ChangesReporting/Output/Factory/JsonOutputFactory.php
new file mode 100644
index 00000000000..aa75152d3ab
--- /dev/null
+++ b/src/ChangesReporting/Output/Factory/JsonOutputFactory.php
@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\ChangesReporting\Output\Factory;
+
+use Nette\Utils\Json;
+use Rector\Parallel\ValueObject\Bridge;
+use Rector\ValueObject\Configuration;
+use Rector\ValueObject\Error\SystemError;
+use Rector\ValueObject\ProcessResult;
+
+/**
+ * @see \Rector\Tests\ChangesReporting\Output\Factory\JsonOutputFactoryTest
+ */
+final class JsonOutputFactory
+{
+    public static function create(ProcessResult $processResult, Configuration $configuration): string
+    {
+        $errorsJson = [
+            'totals' => [
+                'changed_files' => $processResult->getTotalChanged(),
+            ],
+        ];
+
+        // We need onlyWithChanges: false to include all file diffs
+        $fileDiffs = $processResult->getFileDiffs(onlyWithChanges: false);
+        ksort($fileDiffs);
+        foreach ($fileDiffs as $fileDiff) {
+            $filePath = $configuration->isReportingWithRealPath()
+                ? ($fileDiff->getAbsoluteFilePath() ?? '')
+                : $fileDiff->getRelativeFilePath()
+            ;
+
+            if ($configuration->shouldShowDiffs() && $fileDiff->getDiff() !== '') {
+                $errorsJson[Bridge::FILE_DIFFS][] = [
+                    'file' => $filePath,
+                    'diff' => $fileDiff->getDiff(),
+                    'applied_rectors' => $fileDiff->getRectorClasses(),
+                ];
+            }
+
+            // for Rector CI
+            $errorsJson['changed_files'][] = $filePath;
+        }
+
+        $systemErrors = $processResult->getSystemErrors();
+        $errorsJson['totals']['errors'] = count($systemErrors);
+
+        $errorsData = self::createErrorsData($systemErrors, $configuration->isReportingWithRealPath());
+        if ($errorsData !== []) {
+            $errorsJson['errors'] = $errorsData;
+        }
+
+        return Json::encode($errorsJson, pretty: true);
+    }
+
+    /**
+     * @param SystemError[] $errors
+     * @return mixed[]
+     */
+    private static function createErrorsData(array $errors, bool $absoluteFilePath): array
+    {
+        $errorsData = [];
+
+        foreach ($errors as $error) {
+            $errorDataJson = [
+                'message' => $error->getMessage(),
+                'file' => $absoluteFilePath ? $error->getAbsoluteFilePath() : $error->getRelativeFilePath(),
+            ];
+
+            if ($error->getRectorClass() !== null) {
+                $errorDataJson['caused_by'] = $error->getRectorClass();
+            }
+
+            if ($error->getLine() !== null) {
+                $errorDataJson['line'] = $error->getLine();
+            }
+
+            $errorsData[] = $errorDataJson;
+        }
+
+        return $errorsData;
+    }
+}
diff --git a/src/ChangesReporting/Output/JsonOutputFormatter.php b/src/ChangesReporting/Output/JsonOutputFormatter.php
index 65062a4bb8e..7064487d25c 100644
--- a/src/ChangesReporting/Output/JsonOutputFormatter.php
+++ b/src/ChangesReporting/Output/JsonOutputFormatter.php
@@ -4,11 +4,9 @@
 
 namespace Rector\ChangesReporting\Output;
 
-use Nette\Utils\Json;
 use Rector\ChangesReporting\Contract\Output\OutputFormatterInterface;
-use Rector\Parallel\ValueObject\Bridge;
+use Rector\ChangesReporting\Output\Factory\JsonOutputFactory;
 use Rector\ValueObject\Configuration;
-use Rector\ValueObject\Error\SystemError;
 use Rector\ValueObject\ProcessResult;
 
 final readonly class JsonOutputFormatter implements OutputFormatterInterface
@@ -25,67 +23,6 @@ public function getName(): string
 
     public function report(ProcessResult $processResult, Configuration $configuration): void
     {
-        $errorsJson = [
-            'totals' => [
-                'changed_files' => $processResult->getTotalChanged(),
-            ],
-        ];
-
-        $fileDiffs = $processResult->getFileDiffs();
-        ksort($fileDiffs);
-        foreach ($fileDiffs as $fileDiff) {
-            $filePath = $configuration->isReportingWithRealPath()
-                ? ($fileDiff->getAbsoluteFilePath() ?? '')
-                : $fileDiff->getRelativeFilePath()
-            ;
-
-            $errorsJson[Bridge::FILE_DIFFS][] = [
-                'file' => $filePath,
-                'diff' => $fileDiff->getDiff(),
-                'applied_rectors' => $fileDiff->getRectorClasses(),
-            ];
-
-            // for Rector CI
-            $errorsJson['changed_files'][] = $filePath;
-        }
-
-        $systemErrors = $processResult->getSystemErrors();
-        $errorsJson['totals']['errors'] = count($systemErrors);
-
-        $errorsData = $this->createErrorsData($systemErrors, $configuration->isReportingWithRealPath());
-        if ($errorsData !== []) {
-            $errorsJson['errors'] = $errorsData;
-        }
-
-        $json = Json::encode($errorsJson, pretty: true);
-        echo $json . PHP_EOL;
-    }
-
-    /**
-     * @param SystemError[] $errors
-     * @return mixed[]
-     */
-    private function createErrorsData(array $errors, bool $absoluteFilePath): array
-    {
-        $errorsData = [];
-
-        foreach ($errors as $error) {
-            $errorDataJson = [
-                'message' => $error->getMessage(),
-                'file' => $absoluteFilePath ? $error->getAbsoluteFilePath() : $error->getRelativeFilePath(),
-            ];
-
-            if ($error->getRectorClass() !== null) {
-                $errorDataJson['caused_by'] = $error->getRectorClass();
-            }
-
-            if ($error->getLine() !== null) {
-                $errorDataJson['line'] = $error->getLine();
-            }
-
-            $errorsData[] = $errorDataJson;
-        }
-
-        return $errorsData;
+        echo JsonOutputFactory::create($processResult, $configuration) . PHP_EOL;
     }
 }
diff --git a/tests/ChangesReporting/Output/Factory/JsonOutputFactoryTest.php b/tests/ChangesReporting/Output/Factory/JsonOutputFactoryTest.php
new file mode 100644
index 00000000000..5f7a467b910
--- /dev/null
+++ b/tests/ChangesReporting/Output/Factory/JsonOutputFactoryTest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\ChangesReporting\Output\Factory;
+
+use PHPUnit\Framework\TestCase;
+use Rector\ChangesReporting\Output\Factory\JsonOutputFactory;
+use Rector\ChangesReporting\ValueObject\RectorWithLineChange;
+use Rector\Php80\Rector\Identical\StrStartsWithRector;
+use Rector\ValueObject\Configuration;
+use Rector\ValueObject\Error\SystemError;
+use Rector\ValueObject\ProcessResult;
+use Rector\ValueObject\Reporting\FileDiff;
+
+final class JsonOutputFactoryTest extends TestCase
+{
+    public function testReportShouldShowNumberOfChangesWithNoDiffs(): void
+    {
+        $actualOutput = JsonOutputFactory::create(
+            new ProcessResult(
+                [new SystemError('Some error message', 'some/file.php', 1)],
+                [
+                    new FileDiff(
+                        'some/file.php',
+                        '--- Original' . PHP_EOL . '+++ New' . PHP_EOL .
+                            '@@ -38,5 +39,6 @@' . PHP_EOL .
+                            'return true;' . PHP_EOL . '}' . PHP_EOL,
+                        'diff console formatted',
+                        [new RectorWithLineChange(StrStartsWithRector::class, 38)]
+                    ),
+                    new FileDiff(
+                        'some/file_foo.php',
+                        '',
+                        '',
+                        [new RectorWithLineChange(StrStartsWithRector::class, 38)]
+                    ),
+                ],
+                2
+            ),
+            new Configuration(showDiffs: false)
+        );
+
+        $expectedOutput = (string) file_get_contents(__DIR__ . '/../Fixtures/without_diffs.json');
+        $this->assertSame($expectedOutput, $actualOutput);
+    }
+}
diff --git a/tests/ChangesReporting/Output/Fixtures/without_diffs.json b/tests/ChangesReporting/Output/Fixtures/without_diffs.json
new file mode 100644
index 00000000000..d15f37f36de
--- /dev/null
+++ b/tests/ChangesReporting/Output/Fixtures/without_diffs.json
@@ -0,0 +1,17 @@
+{
+    "totals": {
+        "changed_files": 2,
+        "errors": 1
+    },
+    "changed_files": [
+        "some/file.php",
+        "some/file_foo.php"
+    ],
+    "errors": [
+        {
+            "message": "Some error message",
+            "file": "some/file.php",
+            "line": 1
+        }
+    ]
+}
\ No newline at end of file