# FlutterMain.setIsRunningInRobolectricTest on Android removed

> The test-only FlutterMain.setIsRunningInRobolectricTest API on the Android engine is consolidated into the FlutterInjector.




:::important
These breaking change docs are accurate, as of the release
under which they are published. Over time, the
workarounds described here might become inaccurate.
We don't, in general, keep these breaking change docs up
to date as of each release.

这些破坏性改动文档的准确性仅限于其发布时对应的版本。
随着时间的推移，文档中描述的方案可能会逐渐失效。
通常情况下，我们不会在每次发布新版本时都对这些文档进行同步更新。

The [breaking change index file](/release/breaking-changes)
lists the docs created for each release.

[破坏性改动列表](/release/breaking-changes) 
列出了每个版本的文档。

:::


## Summary

If you write Java JUnit tests (such as Robolectric tests)
against the Flutter engine's Java embedding and used the
`FlutterMain.setIsRunningInRobolectricTest(true)` API,
replace it with the following:

```java
FlutterJNI mockFlutterJNI = mock(FlutterJNI.class);
FlutterInjector.setInstance(
        new FlutterInjector.Builder()
            .setFlutterLoader(new FlutterLoader(mockFlutterJNI))
            .build());
```

This should be very uncommon.

## Context

The `FlutterMain` class itself is being deprecated and replaced with the
`FlutterInjector` class. The `FlutterMain` class uses a number of
static variables and functions than make it difficult to test.
`FlutterMain.setIsRunningInRobolectricTest()` is one ad-hoc static
mechanism to allow tests to run on the host machine on JVM without
loading the `libflutter.so` native library
(which can't be done on the host machine).

Rather than one-off solutions, all dependency injections needed for tests
in Flutter's Android/Java engine embedding are now moved to the
[`FlutterInjector`] class.

[`FlutterInjector`]: https://cs.opensource.google/flutter/engine/+/master:shell/platform/android/io/flutter/FlutterInjector.java

Within the `FlutterInjector` class,
the `setFlutterLoader()` Builder
function allows for control of how the
[`FlutterLoader`][] class locates and loads
the `libflutter.so` library.

[`FlutterLoader`]: https://cs.opensource.google/flutter/engine/+/master:shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java

## Description of change

This [engine commit][] removed the
`FlutterMain.setIsRunningInRobolectricTest()` testing function;
and the following [commit][] added a
`FlutterInjector` class to assist testing.
[PR 20473][] further refactored `FlutterLoader`
and `FlutterJNI` to allow for additional mocking and testing.

[commit]: https://github.com/flutter/engine/commit/15f5696c4139a21e1fc54014ce17d01f6ad1737c#diff-f928557f2d60773a8435366400fa42ed
[engine commit]: https://github.com/flutter/engine/commit/15f5696c4139a21e1fc54014ce17d01f6ad1737c#diff-599e1d64442183ead768757cca6805c3L154
[PR 20473]: https://github.com/flutter/engine/pull/20473
to allow for additional mocking/testing.

## Migration guide

Code before migration:

```java
FlutterMain.setIsRunningInRobolectricTest(true);
```

Code after migration:

```java
FlutterJNI mockFlutterJNI = mock(FlutterJNI.class);
FlutterInjector.setInstance(
        new FlutterInjector.Builder()
            .setFlutterLoader(new FlutterLoader(mockFlutterJNI))
            .build());
```

## Timeline

Landed in version: 1.22.0-2.0.pre.133<br>
In stable release: 2.0.0