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Custom asserts: a supported way to test that an assertion fails #916

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Custom asserts: a supported way to test that an assertion fails#916
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enhancementNew feature or requestpure testingPure testing related

Description

@Chemaclass
Chemaclass
opened on Jul 28, 2026

Background

There is no supported way to test that a custom assertion fails the way you intended. To check its failure output you have to reconstruct the expected string from an internal renderer.

bashunit's own suite does exactly that, in tests/functional/custom_asserts_test.sh:

functiontest_assert_foo_failed() {
assert_same "$(bashunit::console_results::print_failed_test "Assert foo failed""foo""but got ""bar")" \
"$(assert_foo "bar")"
}

tests/unit/custom_assertions_test.sh goes further and monkey-patches bashunit::console_results::print_line inside a subshell to capture output.

If the framework has to break its own encapsulation to test a custom assertion, a user has no chance. It also means any change to the failure renderer breaks those tests for reasons unrelated to the assertion under test.

Proposal

Two assertions for asserting about assertions:

assert_assertion_fails <cmd> [args...]
assert_assertion_passes <cmd> [args...]

Each one runs the command with the assertion counters snapshotted, restores them afterwards so the inner assertion does not pollute the test's own totals, and reports a single assertion of its own.

functiontest_assert_positive_number_rejects_zero() {
assert_assertion_fails assert_positive_number 0
}
functiontest_assert_positive_number_accepts_one() {
assert_assertion_passes assert_positive_number 1
}

An optional message check keeps the output contract testable without touching console_results:

assert_assertion_fails_with "positive number" assert_positive_number 0

Notes

  • The counter snapshot and restore is the load-bearing part. Without it, the inner failure leaves _BASHUNIT_ASSERTION_FAILED_IN_TEST set, and every later assertion in the same test is skipped when stop-on-assertion-failure is on (src/assert.sh:10).
  • Once this exists, tests/functional/custom_asserts_test.sh and tests/unit/custom_assertions_test.sh should be rewritten on top of it, which is the real proof that the API is good enough.

Part of a custom-asserts DX set, each sized as its own PR:

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enhancementNew feature or requestpure testingPure testing related

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try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
Custom asserts: a supported way to test that an assertion fails · Issue #916 · TypedDevs/bashunit · GitHub
Skip to content
Custom asserts: a supported way to test that an assertion fails #916
Closed
Closed
Custom asserts: a supported way to test that an assertion fails#916
Assignees
Chemaclass
Labels
enhancementNew feature or requestpure testingPure testing related
Description
@Chemaclass
Chemaclass
opened on Jul 28, 2026
Background
There is no supported way to test that a custom assertion fails the way you intended. To check its failure output you have to reconstruct the expected string from an internal renderer.
bashunit's own suite does exactly that, in tests/functional/custom_asserts_test.sh:
functiontest_assert_foo_failed() {
assert_same "$(bashunit::console_results::print_failed_test "Assert foo failed""foo""but got ""bar")" \
"$(assert_foo "bar")"
}
tests/unit/custom_assertions_test.sh goes further and monkey-patches bashunit::console_results::print_line inside a subshell to capture output.
If the framework has to break its own encapsulation to test a custom assertion, a user has no chance. It also means any change to the failure renderer breaks those tests for reasons unrelated to the assertion under test.
Proposal
Two assertions for asserting about assertions:
assert_assertion_fails <cmd> [args...]
assert_assertion_passes <cmd> [args...]
Each one runs the command with the assertion counters snapshotted, restores them afterwards so the inner assertion does not pollute the test's own totals, and reports a single assertion of its own.
functiontest_assert_positive_number_rejects_zero() {
assert_assertion_fails assert_positive_number 0
}
functiontest_assert_positive_number_accepts_one() {
assert_assertion_passes assert_positive_number 1
}
An optional message check keeps the output contract testable without touching console_results:
assert_assertion_fails_with "positive number" assert_positive_number 0
Notes
  • The counter snapshot and restore is the load-bearing part. Without it, the inner failure leaves _BASHUNIT_ASSERTION_FAILED_IN_TEST set, and every later assertion in the same test is skipped when stop-on-assertion-failure is on (src/assert.sh:10).
  • Once this exists, tests/functional/custom_asserts_test.sh and tests/unit/custom_assertions_test.sh should be rewritten on top of it, which is the real proof that the API is good enough.
Part of a custom-asserts DX set, each sized as its own PR:
Metadata
Metadata
Assignees
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enhancementNew feature or requestpure testingPure testing related
Type
No type
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bashunit
Status
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, 'i');
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style.textContent = '
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color-scheme: dark light;
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} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Custom asserts: a supported way to test that an assertion fails · Issue #916 · TypedDevs/bashunit · GitHub
Skip to content
Custom asserts: a supported way to test that an assertion fails #916
Closed
Closed
Custom asserts: a supported way to test that an assertion fails#916
Assignees
Chemaclass
Labels
enhancementNew feature or requestpure testingPure testing related
Description
@Chemaclass
Chemaclass
opened on Jul 28, 2026
Background
There is no supported way to test that a custom assertion fails the way you intended. To check its failure output you have to reconstruct the expected string from an internal renderer.
bashunit's own suite does exactly that, in tests/functional/custom_asserts_test.sh:
functiontest_assert_foo_failed() {
assert_same "$(bashunit::console_results::print_failed_test "Assert foo failed""foo""but got ""bar")" \
"$(assert_foo "bar")"
}
tests/unit/custom_assertions_test.sh goes further and monkey-patches bashunit::console_results::print_line inside a subshell to capture output.
If the framework has to break its own encapsulation to test a custom assertion, a user has no chance. It also means any change to the failure renderer breaks those tests for reasons unrelated to the assertion under test.
Proposal
Two assertions for asserting about assertions:
assert_assertion_fails <cmd> [args...]
assert_assertion_passes <cmd> [args...]
Each one runs the command with the assertion counters snapshotted, restores them afterwards so the inner assertion does not pollute the test's own totals, and reports a single assertion of its own.
functiontest_assert_positive_number_rejects_zero() {
assert_assertion_fails assert_positive_number 0
}
functiontest_assert_positive_number_accepts_one() {
assert_assertion_passes assert_positive_number 1
}
An optional message check keeps the output contract testable without touching console_results:
assert_assertion_fails_with "positive number" assert_positive_number 0
Notes
  • The counter snapshot and restore is the load-bearing part. Without it, the inner failure leaves _BASHUNIT_ASSERTION_FAILED_IN_TEST set, and every later assertion in the same test is skipped when stop-on-assertion-failure is on (src/assert.sh:10).
  • Once this exists, tests/functional/custom_asserts_test.sh and tests/unit/custom_assertions_test.sh should be rewritten on top of it, which is the real proof that the API is good enough.
Part of a custom-asserts DX set, each sized as its own PR:
Metadata
Metadata
Assignees
Labels
enhancementNew feature or requestpure testingPure testing related
Type
No type
Projects
bashunit
Status
Done
Milestone
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None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
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} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
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(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Custom asserts: a supported way to test that an assertion fails · Issue #916 · TypedDevs/bashunit · GitHub
Skip to content
Custom asserts: a supported way to test that an assertion fails #916
Closed
Closed
Custom asserts: a supported way to test that an assertion fails#916
Assignees
Chemaclass
Labels
enhancementNew feature or requestpure testingPure testing related
Description
@Chemaclass
Chemaclass
opened on Jul 28, 2026
Background
There is no supported way to test that a custom assertion fails the way you intended. To check its failure output you have to reconstruct the expected string from an internal renderer.
bashunit's own suite does exactly that, in tests/functional/custom_asserts_test.sh:
functiontest_assert_foo_failed() {
assert_same "$(bashunit::console_results::print_failed_test "Assert foo failed""foo""but got ""bar")" \
"$(assert_foo "bar")"
}
tests/unit/custom_assertions_test.sh goes further and monkey-patches bashunit::console_results::print_line inside a subshell to capture output.
If the framework has to break its own encapsulation to test a custom assertion, a user has no chance. It also means any change to the failure renderer breaks those tests for reasons unrelated to the assertion under test.
Proposal
Two assertions for asserting about assertions:
assert_assertion_fails <cmd> [args...]
assert_assertion_passes <cmd> [args...]
Each one runs the command with the assertion counters snapshotted, restores them afterwards so the inner assertion does not pollute the test's own totals, and reports a single assertion of its own.
functiontest_assert_positive_number_rejects_zero() {
assert_assertion_fails assert_positive_number 0
}
functiontest_assert_positive_number_accepts_one() {
assert_assertion_passes assert_positive_number 1
}
An optional message check keeps the output contract testable without touching console_results:
assert_assertion_fails_with "positive number" assert_positive_number 0
Notes
  • The counter snapshot and restore is the load-bearing part. Without it, the inner failure leaves _BASHUNIT_ASSERTION_FAILED_IN_TEST set, and every later assertion in the same test is skipped when stop-on-assertion-failure is on (src/assert.sh:10).
  • Once this exists, tests/functional/custom_asserts_test.sh and tests/unit/custom_assertions_test.sh should be rewritten on top of it, which is the real proof that the API is good enough.
Part of a custom-asserts DX set, each sized as its own PR:
Metadata
Metadata
Assignees
Labels
enhancementNew feature or requestpure testingPure testing related
Type
No type
Projects
bashunit
Status
Done
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
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(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
Custom asserts: a supported way to test that an assertion fails · Issue #916 · TypedDevs/bashunit · GitHub
Skip to content
Custom asserts: a supported way to test that an assertion fails #916
Closed
Closed
Custom asserts: a supported way to test that an assertion fails#916
Assignees
Chemaclass
Labels
enhancementNew feature or requestpure testingPure testing related
Description
@Chemaclass
Chemaclass
opened on Jul 28, 2026
Background
There is no supported way to test that a custom assertion fails the way you intended. To check its failure output you have to reconstruct the expected string from an internal renderer.
bashunit's own suite does exactly that, in tests/functional/custom_asserts_test.sh:
functiontest_assert_foo_failed() {
assert_same "$(bashunit::console_results::print_failed_test "Assert foo failed""foo""but got ""bar")" \
"$(assert_foo "bar")"
}
tests/unit/custom_assertions_test.sh goes further and monkey-patches bashunit::console_results::print_line inside a subshell to capture output.
If the framework has to break its own encapsulation to test a custom assertion, a user has no chance. It also means any change to the failure renderer breaks those tests for reasons unrelated to the assertion under test.
Proposal
Two assertions for asserting about assertions:
assert_assertion_fails <cmd> [args...]
assert_assertion_passes <cmd> [args...]
Each one runs the command with the assertion counters snapshotted, restores them afterwards so the inner assertion does not pollute the test's own totals, and reports a single assertion of its own.
functiontest_assert_positive_number_rejects_zero() {
assert_assertion_fails assert_positive_number 0
}
functiontest_assert_positive_number_accepts_one() {
assert_assertion_passes assert_positive_number 1
}
An optional message check keeps the output contract testable without touching console_results:
assert_assertion_fails_with "positive number" assert_positive_number 0
Notes
  • The counter snapshot and restore is the load-bearing part. Without it, the inner failure leaves _BASHUNIT_ASSERTION_FAILED_IN_TEST set, and every later assertion in the same test is skipped when stop-on-assertion-failure is on (src/assert.sh:10).
  • Once this exists, tests/functional/custom_asserts_test.sh and tests/unit/custom_assertions_test.sh should be rewritten on top of it, which is the real proof that the API is good enough.
Part of a custom-asserts DX set, each sized as its own PR:
Metadata
Metadata
Assignees
Labels
enhancementNew feature or requestpure testingPure testing related
Type
No type
Projects
bashunit
Status
Done
Milestone
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Custom asserts: a supported way to test that an assertion fails · Issue #916 · TypedDevs/bashunit · GitHub
Skip to content
Custom asserts: a supported way to test that an assertion fails #916
Closed
Closed
Custom asserts: a supported way to test that an assertion fails#916
Assignees
Chemaclass
Labels
enhancementNew feature or requestpure testingPure testing related
Description
@Chemaclass
Chemaclass
opened on Jul 28, 2026
Background
There is no supported way to test that a custom assertion fails the way you intended. To check its failure output you have to reconstruct the expected string from an internal renderer.
bashunit's own suite does exactly that, in tests/functional/custom_asserts_test.sh:
functiontest_assert_foo_failed() {
assert_same "$(bashunit::console_results::print_failed_test "Assert foo failed""foo""but got ""bar")" \
"$(assert_foo "bar")"
}
tests/unit/custom_assertions_test.sh goes further and monkey-patches bashunit::console_results::print_line inside a subshell to capture output.
If the framework has to break its own encapsulation to test a custom assertion, a user has no chance. It also means any change to the failure renderer breaks those tests for reasons unrelated to the assertion under test.
Proposal
Two assertions for asserting about assertions:
assert_assertion_fails <cmd> [args...]
assert_assertion_passes <cmd> [args...]
Each one runs the command with the assertion counters snapshotted, restores them afterwards so the inner assertion does not pollute the test's own totals, and reports a single assertion of its own.
functiontest_assert_positive_number_rejects_zero() {
assert_assertion_fails assert_positive_number 0
}
functiontest_assert_positive_number_accepts_one() {
assert_assertion_passes assert_positive_number 1
}
An optional message check keeps the output contract testable without touching console_results:
assert_assertion_fails_with "positive number" assert_positive_number 0
Notes
  • The counter snapshot and restore is the load-bearing part. Without it, the inner failure leaves _BASHUNIT_ASSERTION_FAILED_IN_TEST set, and every later assertion in the same test is skipped when stop-on-assertion-failure is on (src/assert.sh:10).
  • Once this exists, tests/functional/custom_asserts_test.sh and tests/unit/custom_assertions_test.sh should be rewritten on top of it, which is the real proof that the API is good enough.
Part of a custom-asserts DX set, each sized as its own PR:
Metadata
Metadata
Assignees
Labels
enhancementNew feature or requestpure testingPure testing related
Type
No type
Projects
bashunit
Status
Done
Milestone
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None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
})();
Custom asserts: a supported way to test that an assertion fails · Issue #916 · TypedDevs/bashunit · GitHub
Skip to content
Custom asserts: a supported way to test that an assertion fails #916
Closed
Closed
Custom asserts: a supported way to test that an assertion fails#916
Assignees
Chemaclass
Labels
enhancementNew feature or requestpure testingPure testing related
Description
@Chemaclass
Chemaclass
opened on Jul 28, 2026
Background
There is no supported way to test that a custom assertion fails the way you intended. To check its failure output you have to reconstruct the expected string from an internal renderer.
bashunit's own suite does exactly that, in tests/functional/custom_asserts_test.sh:
functiontest_assert_foo_failed() {
assert_same "$(bashunit::console_results::print_failed_test "Assert foo failed""foo""but got ""bar")" \
"$(assert_foo "bar")"
}
tests/unit/custom_assertions_test.sh goes further and monkey-patches bashunit::console_results::print_line inside a subshell to capture output.
If the framework has to break its own encapsulation to test a custom assertion, a user has no chance. It also means any change to the failure renderer breaks those tests for reasons unrelated to the assertion under test.
Proposal
Two assertions for asserting about assertions:
assert_assertion_fails <cmd> [args...]
assert_assertion_passes <cmd> [args...]
Each one runs the command with the assertion counters snapshotted, restores them afterwards so the inner assertion does not pollute the test's own totals, and reports a single assertion of its own.
functiontest_assert_positive_number_rejects_zero() {
assert_assertion_fails assert_positive_number 0
}
functiontest_assert_positive_number_accepts_one() {
assert_assertion_passes assert_positive_number 1
}
An optional message check keeps the output contract testable without touching console_results:
assert_assertion_fails_with "positive number" assert_positive_number 0
Notes
  • The counter snapshot and restore is the load-bearing part. Without it, the inner failure leaves _BASHUNIT_ASSERTION_FAILED_IN_TEST set, and every later assertion in the same test is skipped when stop-on-assertion-failure is on (src/assert.sh:10).
  • Once this exists, tests/functional/custom_asserts_test.sh and tests/unit/custom_assertions_test.sh should be rewritten on top of it, which is the real proof that the API is good enough.
Part of a custom-asserts DX set, each sized as its own PR:
Metadata
Metadata
Assignees
Labels
enhancementNew feature or requestpure testingPure testing related
Type
No type
Projects
bashunit
Status
Done
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions