When I build my project with gradle, the test outputs are huge and I would like to keep them. Therefore, I activated showing the output streams:
test {
testLogging.showStandardStreams = true
}
Unfortunately, gradle does not seem to be able to handle big standard outputs. For demonstration, I created a minimal example: https://github.com/DaGeRe/stdout-test It is a project creating big standard output in a test by
@Test
public void test() {
long start = System.currentTimeMillis();
for (int i = 0; i < 200; i++) {
for (int j = 0; j < 10000; j++) {
long current = System.currentTimeMillis() - start;
System.out.println("This is a simple logging output: " + i + " " + j + " " + current);
}
}
}
If I run this in a standard maven project, it finishes in about 2 minutes:
reichelt@reichelt-desktop:~/workspaces/stdout-test$ time mvn test &> mvn.txt
real 1m34,130s
user 0m31,333s
sys 1m12,296s
If I run it in gradle by time ./gradlew test &> gradle.txt, it does not finish at all (in reasonable time) and the output contains many Expiring Daemon because JVM heap space is exhausted. A way to solve this temporarily would be increasing heap memory (like suggested here: JVM space exhausted when building a project through gradle ), but -Xmx4g does not change anything according to my experiments, and this obviously will not scale for bigger outputs. Also, running ./gradlew -i test does not change the behavior.
The project also contains example files for outputs from maven (https://github.com/DaGeRe/stdout-test/blob/master/mvn.txt) and gradle (https://github.com/DaGeRe/stdout-test/blob/master/gradle.txt - aborted process after ~10 minutes) and one of the heap dumps (https://github.com/DaGeRe/stdout-test/blob/master/java_pid10812.hprof.tar) gradle created. There are only minor increases in the current time in the gradle-log (third output number of every line). Therefore, I assume that gradle mainly has problems printing to stdout and not executing the program.
This shows that, while gradle has some problems printing to stdout, it seems to not block the test execution. Is there any switch or parameter I could give gradle, which forces gradle to directly print to stdout instead of doing its memory-intense processing? Unfortunately, I did not find any in the documentation (https://docs.gradle.org/current/dsl/org.gradle.api.tasks.testing.Test.html).
EDIT Just finished a test run on a server:
reichelt@r147:~/workspaces/dissworkspace/stdout-test$ time ./gradlew test &> gradle.txt
real 28m17,959s
user 216m37,351s
sys 0m12,410s
Ends with an exception:
This is a simple logging output: 89 7842 1416
This is a simple logging output: 89 7843 1416
This is a simple logging output: 89 7844 1416
This is a simple logging output: 89 7845 1416
This is a simple logging output: 89 7846 1416
FAILURE: Build failed with an exception.
* What went wrong:
GC overhead limit exceeded
