RFR: 8321812: Update GC tests to use execute[Limited]TestJava [v3]

[Axel Boldt-Christmas]

On Wed, 3 Jan 2024 07:59:48 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> A lot of our tests use a multi-step recipe to spawn and wait for a process. Here's an example
>> 
>>     ProcessBuilder pb = ProcessTools.createTestJavaProcessBuilder(
>>          "-XX:-UseTLAB",
>>          "-XX:+UnlockDiagnosticVMOptions",
>>          "-XX:+VerifyDuringStartup",
>>          "-Xlog:gc+verify=debug",
>>          "-version");
>>     OutputAnalyzer output = new OutputAnalyzer(pb.start());
>>     ... do something with output and wait for the process to complete ...
>> 
>> 
>> These are the steps involved:
>> 
>> 1) Create a `ProcessBuilder`
>> 2) Call `ProcessBuilder::start`
>> 3) Create an `OutputAnalyzer`
>> 4) Perform an operation that finally waits for the process to, at least partially, complete (OutputAnalyzer::getOutput, OutputAnalyzer::shouldHaveExitValue(), and more).
>> 
>> Almost all our tests could be converted to use a single call to `ProcessTools.executeTestJava` (or `executeLimitedTestJava`), which spawns the process, makes sure that it has fully completed, and then returns a filled-in OutputAnalyzer to the caller. The above example would become:
>> 
>> 
>>     OutputAnalyzer output = ProcessTools.executeTestJava(
>>          "-XX:-UseTLAB",
>>          "-XX:+UnlockDiagnosticVMOptions",
>>          "-XX:+VerifyDuringStartup",
>>          "-Xlog:gc+verify=debug",
>>          "-version");
>> 
>> 
>> I propose that we make this change in the GC tests, to make our code simpler and hopefully easier to read.
>> 
>> Note: There's a few changes to the throws statements because some ProcessTools APIs throws IOException while others throw Exception.
>> 
>> Testing: I've done testing on a similar set of changes, but I'm going to run the appropriate, final tests while this is being considered/reviewed.
>
> Stefan Karlsson has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
> 
>  - Merge branch 'rename_executeTestJvm' into 8321812_use_executeTestJava_in_gc_tests
>  - Whitespace fixes
>    
>    Co-authored-by: Thomas Schatzl <59967451+tschatzl at users.noreply.github.com>
>  - 8321812: Update GC tests to use execute[Limited]TestJava

Marked as reviewed by aboldtch (Reviewer).

test/hotspot/jtreg/gc/g1/TestSharedArchiveWithPreTouch.java line 62:

> 60:         dump_args.addAll(Arrays.asList(new String[] { "-Xshare:dump", "-Xlog:cds" }));
> 61: 
> 62:         pb = ProcessTools.createLimitedTestJavaProcessBuilder(dump_args);

-        ProcessBuilder pb;
``` 
Above no longer used.

test/hotspot/jtreg/gc/testlibrary/Helpers.java line 105:

> 103: 
> 104:         ProcessBuilder pb = new ProcessBuilder(jar.getCommand());
> 105:         OutputAnalyzer output = ProcessTools.executeProcess(pb);

The pattern

OutputAnalyzer output = ProcessTools.executeProcess(jcmd.getCommand());

is used above, but an explicit `ProcessBuilder` is used here. Maybe one style should be picked?

`test/hotspot/jtreg/gc/arguments/TestUseCompressedOopsFlagsWithUlimit.java` does something similar to this as well.

-------------

PR Review: https://git.openjdk.org/jdk/pull/17067#pullrequestreview-1801558649
PR Review Comment: https://git.openjdk.org/jdk/pull/17067#discussion_r1440185432
PR Review Comment: https://git.openjdk.org/jdk/pull/17067#discussion_r1440191965