std.test.assertContains

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.

```text assertNe failed: both values are {value} ```

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

```text 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.