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src/build/android/docs/coverage.md
Finnur Thorarinsson ab966867f2 Fix documentation for Android code coverage generation.
The instructions seem to assume running the script from /src and
the intent is to create two directories

/tmp/coverage
/tmp/coverage_report

but the lack of a slash prefix results in the creation of...

/tmp/coverage
/src/tmp/coverage_report

Bug: None
Change-Id: Ib10050a577fc8e9494a903386d5886ccbef8aa1e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2124256
Commit-Queue: John Budorick <jbudorick@chromium.org>
Reviewed-by: Yun Liu <yliuyliu@google.com>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754026}
2020-03-27 15:31:38 +00:00

74 lines
2.3 KiB
Markdown

# Android code coverage instructions
These are instructions for collecting code coverage data for android
instrumentation and JUnit tests.
[TOC]
## How JaCoCo coverage works
In order to use JaCoCo code coverage, we need to create build time pre-instrumented
class files and runtime **.exec** files. Then we need to process them using the
**build/android/generate_jacoco_report.py** script.
## How to collect coverage data
1. Use the following GN build arguments:
```gn
target_os = "android"
use_jacoco_coverage = true
```
Now when building, pre-instrumented files will be created in the build directory.
2. Run tests, with option `--coverage-dir <directory>`, to specify where to save
the .exec file. For example, you can run chrome JUnit tests:
`out/Debug/bin/run_chrome_junit_tests --coverage-dir /tmp/coverage`.
3. The coverage results of JUnit and instrumentation tests will be merged
automatically if they are in the same directory.
## How to generate coverage report
1. Now we have generated .exec files already. We can create a JaCoCo HTML/XML/CSV
report using `generate_jacoco_report.py`, for example:
```shell
build/android/generate_jacoco_report.py \
--format html \
--output-dir /tmp/coverage_report/ \
--coverage-dir /tmp/coverage/ \
--sources-json-dir out/Debug/ \
```
Then an index.html containing coverage info will be created in output directory:
```
[INFO] Loading execution data file /tmp/coverage/testTitle.exec.
[INFO] Loading execution data file /tmp/coverage/testSelected.exec.
[INFO] Loading execution data file /tmp/coverage/testClickToSelect.exec.
[INFO] Loading execution data file /tmp/coverage/testClickToClose.exec.
[INFO] Loading execution data file /tmp/coverage/testThumbnail.exec.
[INFO] Analyzing 58 classes.
```
2. For XML and CSV reports, we need to specify `--output-file` instead of `--output-dir` since
only one file will be generated as XML or CSV report.
```shell
build/android/generate_jacoco_report.py \
--format xml \
--output-file /tmp/coverage_report/report.xml \
--coverage-dir /tmp/coverage/ \
--sources-json-dir out/Debug/ \
```
or
```shell
build/android/generate_jacoco_report.py \
--format csv \
--output-file /tmp/coverage_report/report.csv \
--coverage-dir /tmp/coverage/ \
--sources-json-dir out/Debug/ \
```