What is the purpose of @SmallTest, @MediumTest, and @LargeTest annotations in Android?

Question

I'm new to Android and I've seen example code using these annotations. For example:

@SmallTest
public void testStuff() {
    TouchUtils.tapView(this, anEditTextView);
    sendKeys("H E L P SPACE M E PERIOD");
    assertEquals("help me.", anEditTextView.getText().toString());
}

What does that annotation accomplish?

score 153 · Answer 1 · edited Mar 30 '22 at 14:08

153

This blog post explains it best. Basically, it is the following:

Small: this test doesn't interact with any file system or network.
Medium: Accesses file systems on box which is running tests.
Large: Accesses external file systems, networks, etc.

Per the Android Developers blog, a small test should take < 100ms, a medium test < 2s, and a large test < 120s.

The answer from azizbekian shows how to utilize the annotation when running your tests.

Also, this old out-of-date page has even more information. Specifically, how to use the am instrument tool with adb shell. Here's the pertinent parts:

am instrument options

The am instrument tool passes testing options to InstrumentationTestRunner or a subclass in the form of key-value pairs, using the -e flag, with this syntax:

-e <key> <value>

Some keys accept multiple values. You specify multiple values in a comma-separated list. For example, this invocation of InstrumentationTestRunner provides multiple values for the package key:

$ adb shell am instrument -w -e package com.android.test.package1,com.android.test.package2 \
> com.android.test/android.test.InstrumentationTestRunner

The following table describes the key-value pairs and their result. Please review the Usage Notes following the table.

Key	Value	Description
size	[small \| medium \| large]	Runs a test method annotated by size. The annotations are @SmallTest, @MediumTest, and @LargeTest.

So reading the above, you could specify small tests like this:

$ adb shell am instrument -w \
>   -e package com.android.test.package1,com.android.test.package2 \
>   -e size small \
>  com.android.test/android.test.InstrumentationTestRunner

edited Mar 30 '22 at 14:08

Eric Palakovich Carr

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answered Jan 12 '11 at 17:39

David Weiser

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I see (and remember reading that article last month). But in the context of the code above, does it actually DO anything except leave a note for other developers? Does it enforce anything? Are there any tools that utilizes this annotation? What's it's purpose in Android development? – Eric Palakovich Carr Jan 12 '11 at 17:58
3

@Eric The Android TestRunner allows you to specify what size of tests to run. – Cheryl Simon Jan 12 '11 at 18:12
Ah, I see. There's quite a bit of Android docs for me to get through still. I suppose this is a good thing. Thanks David and Mayra. – Eric Palakovich Carr Jan 13 '11 at 05:38
7

There is a newer blog from Google on this matter: https://plus.google.com/+AndroidDevelopers/posts/TPy1EeSaSg8 – k29 Apr 19 '14 at 20:33
1

@SmallTest is deprecated – Neon Warge Sep 10 '16 at 13:02
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@NeonWarge use import android.support.test.filters.[Small]Test; – Alexander Sidikov Pfeif Oct 14 '16 at 13:22
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"See this page (search for "@SmallTest") on how to specify which tests get run." - that's the exact reason why link-only answers are discouraged. – arekolek Oct 14 '17 at 11:43
That doesn't really answer the question? Is it a documentation only, a hint for a test runtime, somehow enforced policy? – CheatEx Jul 06 '18 at 10:14
1

Last link is broken – Zeek Aran Dec 13 '18 at 17:58

azizbekian · Accepted Answer · 2020-05-19T08:48:04.730

15

As an addition to Davidann's answer and mainly OP's question in the comment:

In the context of the code above, does it actually DO anything except leave a note for other developers? Does it enforce anything? Are there any tools that utilizes this annotation? What's it's purpose in Android development?

You can run a group of tests annotated with specific annotation.

From AndroidJUnitRunner documentation:

Running a specific test size i.e. annotated with SmallTest or MediumTest or LargeTest:

adb shell am instrument -w -e size [small|medium|large] com.android.foo/android.support.test.runner.AndroidJUnitRunner

You may also setup those params through gradle:


    android {
        ...
        defaultConfig {
            ...
            testInstrumentationRunnerArgument 'size', 'Large'
        }
    }

Via gradle:

-Pandroid.testInstrumentationRunnerArguments.size=small

See Doug Stevenson blog post as well as this blog post for more details.

edited May 19 '20 at 08:48

answered Aug 11 '17 at 14:02

azizbekian

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OK, so in short I can run only @SmallTest test suite with `adb shell am instrument -w -e size small com.android.foo/android.support.test.runner.AndroidJUnitRunner`; thanks – kosiara - Bartosz Kosarzycki Aug 09 '18 at 08:29
How do we specify the annotation in a gradle command? For example, something like: `./gradlew connectedDebugAndroidTest -size MediumTest` – Mr-IDE Aug 06 '19 at 07:39
@Mr-IDE, did you get the answer? – John May 19 '20 at 07:59

score 2 · Answer 3 · answered Feb 28 '18 at 11:53

2

You can also annotate POJO unit tests with @Category(MediumTest.class) or @Category(LargeTest.class), etc. by defining your own Categories - see the test-categories repo for an example

answered Feb 28 '18 at 11:53

Rhisiart

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What is the purpose of @SmallTest, @MediumTest, and @LargeTest annotations in Android?

3 Answers3

am instrument options

Linked