mongo/bazel/resmoke

Resmoke Bazel Rules

Rules for running resmoke test suites in Bazel.

resmoke_suite_test

Runs a resmoke test suite in Bazel.

This rule generates a resmoke configuration file based on the provided test sources and base config, then executes the tests using the resmoke.py test runner.

EXAMPLE

load("//bazel/resmoke:resmoke.bzl", "resmoke_suite_test")

resmoke_suite_test(
    name = "jscore",
    config = "//buildscripts/resmokeconfig/suites:core.yml",
    srcs = ["//jstests/core:all_subpackage_javascript_files"],
    exclude_with_any_tags = ["requires_sharding"],
    deps = [
        "//src/mongo/db:mongod",
        "//src/mongo/shell:mongo",
    ],
)

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this test target.	Name	required
config	The base resmoke YAML configuration file for the suite. This provides the default configuration that will be augmented with the selected tests.	Label	required
srcs	Test files to include in the suite. These files are written as the 'roots' of the test selector in the generated configuration. Typically JavaScript test files for jstest suites.	List of labels	required
data	Additional files required by the tests during runtime. Typically JavaScript files from jstests/libs.	List of labels	optional	[]
deps	MongoDB binaries and other executables that the tests depend on (e.g., mongod, mongos). These are placed on the PATH when running the test suite.	List of labels	optional	[]
exclude_files	Test files to explicitly exclude from the suite, even if they appear in srcs.	List of labels	optional	[]
exclude_with_any_tags	List of test tags. Tests with any of these tags will be excluded from the suite.	List of strings	optional	[]
include_with_any_tags	List of test tags. Only tests with at least one of these tags will be included in the suite.	List of strings	optional	[]
resmoke_args	Additional command-line arguments to pass to the resmoke runner.	List of strings	optional	[]
shard_count	The number of parallel shards to split the test suite across. Each shard runs a subset of the tests. See the Test Sharding section below for details.	Integer	optional	None

Test Sharding

Test sharding allows you to split a large test suite across multiple parallel test executions, significantly reducing total test time. When shard_count is specified, Bazel will:

1. Run the test target multiple times in parallel (up to the specified shard count)
2. Each shard receives a unique shard index (0 to N-1)
3. The resmoke runner uses these values to determine which subset of tests to run in each shard
4. Each shard produces its own test output and logs

Note: sharding is an alternative to the resmoke --jobs flag, which should not be used with resmoke_suite_test.

Test Logs and Output Directory

Bazel creates a dedicated output directory for each test run under the bazel-testlogs symlink in your workspace root.

For a test target //buildscripts/resmokeconfig:core, the outputs are like:

bazel-testlogs/buildscripts/resmokeconfig/core/
├── test.log                           # Primary test output log. Contains the output of resmoke.py
├── test.outputs/
│   ├── report.json                    # Test results in JSON format
│   └── data/                          # The data directory for the resmoke fixture
│       └── job0/
│           ├── mongorunner/
│           └── resmoke/
│               ├── WiredTiger*
│               ├── journal/
│               └── diagnostic.data/

Tips and Tricks

Run a single test from a suite:

bazel test //buildscripts/resmokeconfig:core --test_sharding_strategy=disabled --test_arg=jstests/core/js/jssymbol.js

Run resmoke.py outside of bazel with the suite's config:

# Build binaries and the suite's config (the *_config target)
bazel build install-dist-test //buildscripts/resmokeconfig:core_config

python buildscripts/resmoke.py run --suite bazel-bin/buildscripts/resmokeconfig/core.yml