RFR: JDK-8176084 Developer-friendly run-test facility

[Magnus Ihse Bursie]

Oh no, not that one either? This time I made sure it was sent as HTML. 
It's probably the openjdk mailer that converts it. *sigh* :-(

Here's the markdown source, it's probably more readable than the mangled 
mess that got through before.

# TL;DR.

First of all, this does not change or remove any current functionality, 
it only
adds new.

This new way of running tests is developer-centric. It assumes that you 
have
built a jdk locally and want to test it. Running common test targets is 
simple,
and more complex ad-hoc combination of tests is possible. The user 
interface is
forgiving, and clearly report errors it cannot resolve.

Some example command-lines:

     $ make run-test-tier1
     $ make run-test-jdk_lang JTREG="JOBS=8"
     $ make run-test TEST=jdk_lang
     $ make run-test-only TEST="gtest:LogTagSet 
gtest:LogTagSetDescriptions" GTEST="REPEAT=-1"
     $ make run-test TEST="hotspot/test:hotspot_gc" 
JTREG="JOBS=1;TIMEOUT=8;VM_OTIONS=-XshowSettings -Xlog:gc+ref=debug"
     $ make run-test TEST="jtreg:hotspot/test:hotspot_gc 
hotspot/test/native_sanity/JniVersion.java"

# Full description of the run-test framework

## Test selection

All functionality is available using the run-test make target. In this 
use case,
the test or tests to be executed is controlled using the `TEST` 
variable. To speed
up subsequent test runs with no source code changes, run-test-only can 
be used
instead, which do not depend on the source and test image build.

For some common top-level tests, direct make targets have been 
generated. This
includes all JTreg test groups, the hotspot gtest, and custom tests (if
present). This means that `make run-test-tier1` is equivalent to `make 
run-test
TEST="tier1"`, but the latter is more tab-completion friendly. For more 
complex
test runs, the `run-test TEST="x"` solution needs to be used.

The test specifications given in `TEST` is parsed into fully qualified test
descriptors, which clearly and unambigously show which tests will be 
run. As an
example, `:tier1` will expand to `jtreg:jdk/test:tier1
jtreg:langtools/test:tier1 jtreg:nashorn/test:tier1 
jtreg:jaxp/test:tier1`. You
can always submit a list of fully qualified test descriptors in the `TEST`
variable if you want to shortcut the parser.

### JTreg

JTreg test groups can be specified either without a test root, e.g. 
`:tier1` (or
`tier1`, the initial colon is optional), or with, e.g. 
`hotspot/test:tier1`,
`jdk/test:jdk_util`.

When specified without a test root, all matching groups from all tests 
roots
will be added. Otherwise, only the group from the specified test root 
will be
added.

Individual JTreg tests or directories containing JTreg tests can also be
specified, like `hotspot/test/native_sanity/JniVersion.java` or
`hotspot/test/native_sanity`. You can also specify an absolute path, to 
point to
a JTreg test outside the source tree.

As long as the test groups or test paths can be uniquely resolved, you 
do not
need to enter the `jtreg:` prefix. If this is not possible, or if you 
want to
use a fully qualified test descriptor, add `jtreg:`, e.g.
`jtreg:hotspot/test/native_sanity`.

### Gtest

Since the Hotspot Gtest suite is so quick, the default is to run all 
tests. This
is specified by just `gtest`, or as a fully qualified test descriptor
`gtest:all`.

If you want, you can single out an individual test or a group of tests, for
instance `gtest:LogDecorations` or `gtest:LogDecorations.level_test_vm`. 
This
can be particularly useful if you want to run a shaky test repeatedly.

## Test results and summary

At the end of the test run, a summary of all tests run will be 
presented. This
will have a consistent look, regardless of what test suites were used. 
This is a
sample summary:

     ==============================
     Test summary
     ==============================
        TEST                                              TOTAL PASS  
FAIL ERROR
     >> jtreg:jdk/test:tier1 1867  1865     2     0 <<
        jtreg:langtools/test:tier1                         4711 4711     
0     0
        jtreg:nashorn/test:tier1                            133 133     
0     0
     ==============================
     TEST FAILURE

Tests where the number of TOTAL tests does not equal the number of 
PASSed tests
will be considered a test failure. These are marked with the `>> ... <<` 
marker
for easy identification.

The classification of non-passed tests differs a bit between test 
suites. In the
summary, ERROR is used as a catch-all for tests that neither passed nor are
classified as failed by the framework. This might indicate test 
framework error,
timeout or other problems.

Note that `make run-test` will exit with value 0 even in case of test 
failures.
A non-zero exit code will indicate a failure in the run-test framework. 
The last
line printed will show either `TEST FAILURE` or `TEST SUCCESS`, 
depending on how
the test results ended up.

All test have their result stored in 
`build/$BUILD/test-result/$TEST_ID`, where
TEST_ID is a path-safe conversion from the fully qualified test 
descriptor, e.g.
for `jtreg:jdk/test:tier1` the TEST_ID is `jtreg_jdk_test_tier1`. This 
path is
also printed in the log at the end of the test run.

Additional work data is stored in `build/$BUILD/test-support/$TEST_ID`. 
For some
frameworks, this directory might contain information that is useful in
determining the cause of a failed test.

## Test suite control

It is possible to control various aspects of the test suites using make 
control
variables.

These variables use a keyword=value approach to allow multiple values to 
be set.
So, for instance, `JTREG="JOBS=1;TIMEOUT=8"` will set the JTreg 
concurrency level
to 1 and the timeout factor to 8. This is equivalent to setting 
`JTREG_JOBS=1
JTREG_TIMEOUT=8`, but using the keyword format means that the `JTREG` 
variable is
parsed and verified for correctness, so `JTREG="TMIEOUT=8"` would give 
an error,
while `JTREG_TMIEOUT=8` would just pass unnoticed.

To separate multiple keyword=value pairs, use `;` (semicolon). Since the 
shell
normally eats `;`, the recommended usage is to write the assignment 
inside qoutes,
e.g. `JTREG="...;..."`. This will also make sure spaces are preserved, 
as in
`JTREG="VM_OTIONS=-XshowSettings -Xlog:gc+ref=debug"`.

(Other ways are possible, e.g. using backslash: 
`JTREG=JOBS=1\;TIMEOUT=8`. Also,
as a special technique, the string `%20` will be replaced with space for 
certain
options, e.g. `JTREG=VM_OTIONS=-XshowSettings%20-Xlog:gc+ref=debug`. 
This can be
useful if you have layers of scripts and have trouble getting proper 
quoting of
command lines arguments through.)

As far as possible, the names of the keywords have been standardized 
between
test suites.

### JTreg keywords

#### JOBS
The test concurrency (`-concurrency`).

Defaults to TEST_JOBS (if set by `--with-test-jobs=`), otherwise it 
defaults to 1
for hotspot and JOBS for all other components.

#### TIMEOUT
The timeout factor (`-timeoutFactor`).

Defaults to 4.

#### TEST_MODE
The test mode (`-agentvm`, `-samevm` or `-othervm`).

Defaults to `-agentvm`.

#### ASSERT
Enable asserts (`-ea -esa`, or none).

Set to `true` or `false`. If true, adds `-ea -esa`. Defaults to true, 
except for
hotspot.

#### VERBOSE
The verbosity level (`-verbose`).

Defaults to `fail,error,summary`.

#### RETAIN
What test data to retain (`-retain`).

Defaults to `fail,error`.

#### MAX_MEM
Limit memory consumption (`-Xmx` and `-vmoption:-Xmx`, or none).

Limit memory consumption for JTreg test framework and VM under test. Set 
to 0 to
disable the limits.

Defaults to 512m, except for hotspot, where it defaults to 0 (no limit).

#### OPTIONS
Additional options to the JTreg test framework.

Use `JTREG="OPTIONS=--help all"` to see all available JTreg options.

#### JAVA_OPTIONS
Additional Java options to JTreg (`-javaoption`).

#### VM_OPTIONS
Additional VM options to JTreg (`-vmoption`).

### Gtest keywords

#### REPEAT
The number of times to repeat the tests (`--gtest_repeat`).

Default is 1. Set to -1 to repeat indefinitely. This can be especially 
useful
combined with `OPTIONS=--gtest_break_on_failure` to reproduce an 
intermittent
problem.

#### OPTIONS
Additional options to the Gtest test framework.

Use `GTEST="OPTIONS=--help"` to see all available Gtest options.


/Magnus