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BREAKING(assert): assertAlmostEquals() sets useful tolerance automatically #4460

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merged 4 commits into from
Jun 3, 2024
Merged

BREAKING(assert): assertAlmostEquals() sets useful tolerance automatically #4460

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a20a597
feat(assert): assertAlmostEquals() sets useful tolerance automatically
bradenmacdonald Mar 10, 2024
176664b
Merge branch 'main' into assert-almost-equals-auto
kt3k Apr 29, 2024
15d1bfa
Merge branch 'main' into assert-almost-equals-auto
kt3k May 31, 2024
8fdc153
Merge branch 'main' into assert-almost-equals-auto
iuioiua Jun 3, 2024
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12 changes: 10 additions & 2 deletions assert/assert_almost_equals.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -8,26 +8,34 @@ import { AssertionError } from "./assertion_error.ts";
* double-precision floating-point representation limitations. If the values
* are not almost equal then throw.
*
* The default tolerance is one hundred thousandth of a percent of the
* expected value.
*
* @example
* ```ts
* import { assertAlmostEquals } from "@std/assert";
*
* assertAlmostEquals(0.01, 0.02, 0.1); // Doesn't throw
* assertAlmostEquals(0.01, 0.02); // Throws
* assertAlmostEquals(1e-8, 1e-9); // Throws
* assertAlmostEquals(1.000000001e-8, 1.000000002e-8); // Doesn't throw
* assertAlmostEquals(0.01, 0.02, 0.1); // Doesn't throw
* assertAlmostEquals(0.1 + 0.2, 0.3, 1e-16); // Doesn't throw
* assertAlmostEquals(0.1 + 0.2, 0.3, 1e-17); // Throws
* ```
*/
export function assertAlmostEquals(
actual: number,
expected: number,
tolerance = 1e-7,
tolerance?: number,
msg?: string,
) {
if (Object.is(actual, expected)) {
return;
}
const delta = Math.abs(expected - actual);
if (tolerance === undefined) {
tolerance = isFinite(expected) ? expected * 1e-7 : 1e-7;
}
if (delta <= tolerance) {
return;
}
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5 changes: 5 additions & 0 deletions assert/assert_almost_equals_test.ts
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Expand Up @@ -7,11 +7,16 @@ Deno.test("assertAlmostEquals() matches values within default precision range",
assertAlmostEquals(0.1 + 0.2, 0.3);
assertAlmostEquals(NaN, NaN);
assertAlmostEquals(Number.NaN, Number.NaN);
assertAlmostEquals(9e20, 9.0000000001e20);
assertAlmostEquals(1.000000001e-8, 1.000000002e-8);
});

Deno.test("assertAlmostEquals() throws values outside default precision range", () => {
assertThrows(() => assertAlmostEquals(1, 2));
assertThrows(() => assertAlmostEquals(1, 1.1));
assertThrows(() => assertAlmostEquals(9e20, 9.01e20));
assertThrows(() => assertAlmostEquals(5e-7, 6e-7)); // approx 20% different value
assertThrows(() => assertAlmostEquals(1e-8, 1e-9)); // different order of magnitude
});

Deno.test("assertAlmostEquals() matches values within higher precision range", () => {
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