"bazel test //..." executes actions unrelated to any tests - bazel

Question

I have a target //src/hello:hello_proj.bit which should not be a dependency for any tests. This is confirmed by:
$ bazel cquery 'rdeps(//..., //src/hello:hello_proj.bit)' --output=label_kind
INFO: Analyzed 38 targets (0 packages loaded, 0 targets configured).
INFO: Found 38 targets...
vivado_bitstream rule //src/hello:hello_proj.bit (43fd5e3)
vivado_config_memory rule //src/hello:hello_proj.bin (43fd5e3)
vivado_load rule //src/hello:hello_proj.load (43fd5e3)
vivado_flash rule //src/hello:hello_proj.flash (43fd5e3)
INFO: Elapsed time: 0.175s
INFO: 0 processes.
INFO: Build completed successfully, 0 total actions
And:
$ bazel cquery 'allpaths(tests(//...), //src/hello:hello_proj.bit)'
INFO: Analyzed 38 targets (0 packages loaded, 3 targets configured).
INFO: Found 38 targets...
INFO: Empty query results
INFO: Elapsed time: 0.247s
INFO: 0 processes.
INFO: Build completed successfully, 0 total actions
In addition, the following returns no results:
$ bazel aquery 'deps(tests(//...))' | grep hello_proj.bit
But yet the following still tries to build //src/hello:hello_proj.bit even though the tests can complete successfully if --keep_going is issued. So clearly it is not truly a dependecy but ends up in the action graph for some unknown reason.
$ bazel test -s --keep_going //...
INFO: Analyzed 35 targets (0 packages loaded, 0 targets configured).
INFO: Found 26 targets and 9 test targets...
SUBCOMMAND: # //src/hello:hello_proj.bit [action 'Synthesizing hello', configuration: 0decb71fa64362af97ee459b2292a0b5285d3f4092bf077905729774dcbbdb43, execution platform: #local_config_platform//:host]
... Removed for brevity ...
ERROR: /home/agoessling/hdl/src/hello/BUILD:26:15: Synthesizing hello failed (Exit 1):
... Removed for brevity ...
INFO: Elapsed time: 0.339s, Critical Path: 0.18s
INFO: 2 processes: 2 internal.
FAILED: Build did NOT complete successfully
//src/hello:test_hello_ver_BAUD25000000_FREP100000 (cached) PASSED in 0.4s
//src/lib:prove_strobe_div (cached) PASSED in 1.0s
//src/lib:prove_uart_tx (cached) PASSED in 4.2s
//src/lib:test_strobe_div_DIV100 (cached) PASSED in 0.4s
//src/lib:test_strobe_div_DIV2 (cached) PASSED in 0.4s
//src/lib:test_strobe_div_DIV6 (cached) PASSED in 0.3s
//src/lib:test_strobe_div_DIV7 (cached) PASSED in 0.3s
//src/lib:test_strobe_div_DIV8 (cached) PASSED in 0.4s
//src/lib:test_uart_tx_BAUD_DIV3 (cached) PASSED in 0.4s
Executed 0 out of 9 tests: 9 tests pass.
All tests passed but there were other errors during the build.
FAILED: Build did NOT complete successfully
I'm at a loss at what else to try to dig into this. No query, cquery, or aquery that I have tried has yielded any connection from any test to //src/hello:hello_proj.bit. What am I missing?

Answer 1

In bazel, the test verb is essentially "build the given targets and execute any of them that are tests".
//... expands to all targets in the current workspace, which therefore includes //src/hello:hello_proj.bit
So here bazel is building everything (//...) and then running any tests.
To build just the test cases, pass --build_tests_only