std.test.assertEq

The operands of std.test.assertEq(actual, expected) use the ordinary equality domain →.

Equal values return () and execution continues. Unequal values raise TPZ4007 with the rendered actual and expected values.

Known noncomparable operands produce TPZ5007 during checking.

Argument evaluation and assertion failure follow Test comparisons →.

Derivation follows the operation it generates. Eq asks whether two values are equal. Order supplies a total comparison. JSON supplies conversion to and from a JSON tree under the type's documented representation. These are different obligations, so admission is determined by the operation rather than a common whitelist. A nested nominal always uses the conformance described above. This table defines the listed component families; it does not assign capabilities to other built-ins. Duration capabilities follow its operations rule →.

Map and Set equality reuse the key identity already used by lookup and membership. A custom Eq method does not replace stored-key equality. Map values use their Eq operation, including a manual nominal implementation. Insertion order does not affect either equality result. Functions and resources have no data-value equality, and regex denotation has no general equality operation. JSONValue and TOMLValue preserve representation information and require decoding or an explicit projection into the intended equality domain. Templates, ranges, mutable ByteBuffer values, and namespaces likewise have no automatic Eq conformance. Bytes compare bytes; Path and URL compare their canonical representations; Date, BigInt, and Decimal compare their values; Match and RoundingMode retain their declared value equality. IEEE equality is not an equivalence relation for NaN-containing values: NaN differs from itself and positive and negative zero compare equal. Eq does not promise otherwise.

For Order, Bytes compare bytewise; Path and URL compare canonical strings; Date compares calendar days; BigInt and Decimal compare numbers. A record uses sorted field names, including a nominal record, so rearranging declarations cannot change priority. A derived enum compares variant names in Unicode scalar order and then positional payloads. A newtype compares its base. Each component must itself have Order. Map and Set describe membership rather than a selected key order; a heterogeneous union has no declared cross-type priority. A nominal manual implementation can state those application-specific choices. Float keeps its ordinary IEEE relational predicates, which may all be false for NaN, and therefore does not satisfy total Order. Opaque families without a declared total order do not gain one through derivation.

JSON uses the existing record object, enum tag/values object, and transparent newtype representations. Result uses the enum representation rather than treating an Err payload as codec failure. Option converts through null and its payload values. Some(None()) and Some(()) can decode as None(). This normalization can map distinct source values to the same decoded value. JSONValue conversion preserves its tree, including stored number lexemes. Semantic scalar types such as Bytes, Path, URL, Date, BigInt, Decimal, Match, and RoundingMode need an explicitly chosen external schema through a nominal manual JSON implementation. Conversion does not silently pick a binary encoding, path base, unit, precision loss, or tag convention. Functions, resources, and templates cannot be reconstructed as data values. Derived conversion failure is TPZ5530 when a component type has no JSON capability. Malformed data and value-level encoding failures return an Err result during conversion.

Finite float encoding chooses the shortest decimal significand that recovers the identical binary64 value under nearest, ties-to-even decoding. If shortest candidates differ, choose the decimal closest to the exact binary value, then the candidate with an even final significand digit. Render fixed notation when the normalized decimal exponent is at least -6 and below 21; otherwise use lowercase e, with no plus sign or redundant exponent zeroes. Omit redundant fractional zeroes. Positive zero is 0 and negative zero is -0. A nonfinite input returns Err without substituting null or a string. Decoding accepts any JSON number, including integer lexemes, rounds once to binary64 with nearest, ties-to-even, preserves a negative zero sign, and rejects overflow to a nonfinite result. Underflow rounds to a finite subnormal or signed zero. The shortest-number rule applies when encoding a float; parsing and re-serializing an existing JSONValue preserves its accepted number lexeme, and numberText/asInt retain their existing semantics. Recursive conversion follows the depth rule above and value semantics →. Show remains the total debug-render operation and has no member capability gate.

Test programs iterate supplied values with the ordinary for statement. The same statement applies to integers, booleans, strings, and other iterable element types.

std.test does not export forAllInt or forAllBool. Assertions inside a for body retain the same assertion behavior as a direct call.

assertNe(actual, expected) returns unit when ordinary value equality says the operands differ. It performs no string conversion before comparison.

The operands must have a common comparable type under the ordinary equality rules. Known noncomparable values produce TPZ5007 during checking. A comparison fault propagates with its own diagnostic.

assertContains(text, needle) returns unit when the exact needle occurs as a contiguous substring. Matching is case sensitive and preserves Unicode spelling. An empty needle succeeds even when the text is empty.

Arguments are evaluated once from left to right before testing the condition. Successful calls have no further side effects and print nothing.

A false assertion raises TPZ4007 at the assertion call. It returns no value and stops the current test before the next statement. Earlier argument side effects remain visible. Test runner handling of later test cases follows the test execution contract.

The inequality failure message uses the ordinary rendering of the shared value in this form.

assertNe failed: both values are `{value}`

The containment failure message includes the original text and needle in this form.

assertContains failed: `{text}` does not contain `{needle}`

These assertions add test failure reporting to ordinary equality and string containment. They do not define a separate comparison relation.

assertNe(actual, expected) returns unit when ordinary value equality says the operands differ. It performs no string conversion before comparison.

The operands must have a common comparable type under the ordinary equality rules. Known noncomparable values produce TPZ5007 during checking. A comparison fault propagates with its own diagnostic.

assertContains(text, needle) returns unit when the exact needle occurs as a contiguous substring. Matching is case sensitive and preserves Unicode spelling. An empty needle succeeds even when the text is empty.

Arguments are evaluated once from left to right before testing the condition. Successful calls have no further side effects and print nothing.

A false assertion raises TPZ4007 at the assertion call. It returns no value and stops the current test before the next statement. Earlier argument side effects remain visible. Test runner handling of later test cases follows the test execution contract.

The inequality failure message uses the ordinary rendering of the shared value in this form.

assertNe failed: both values are `{value}`

The containment failure message includes the original text and needle in this form.

assertContains failed: `{text}` does not contain `{needle}`

These assertions add test failure reporting to ordinary equality and string containment. They do not define a separate comparison relation.

The operands of std.test.assertEq(actual, expected) use the ordinary equality domain →.

Equal values return () and execution continues. Unequal values raise TPZ4007 with the rendered actual and expected values.

Known noncomparable operands produce TPZ5007 during checking.

Argument evaluation and assertion failure follow Test comparisons →.

assertNe(actual, expected) returns unit when ordinary value equality says the operands differ. It performs no string conversion before comparison.

The operands must have a common comparable type under the ordinary equality rules. Known noncomparable values produce TPZ5007 during checking. A comparison fault propagates with its own diagnostic.

assertContains(text, needle) returns unit when the exact needle occurs as a contiguous substring. Matching is case sensitive and preserves Unicode spelling. An empty needle succeeds even when the text is empty.

Arguments are evaluated once from left to right before testing the condition. Successful calls have no further side effects and print nothing.

A false assertion raises TPZ4007 at the assertion call. It returns no value and stops the current test before the next statement. Earlier argument side effects remain visible. Test runner handling of later test cases follows the test execution contract.

The inequality failure message uses the ordinary rendering of the shared value in this form.

assertNe failed: both values are `{value}`

The containment failure message includes the original text and needle in this form.

assertContains failed: `{text}` does not contain `{needle}`

These assertions add test failure reporting to ordinary equality and string containment. They do not define a separate comparison relation.