Anys: Pytest Matchers

0.3.1 · active · verified Sun Apr 12

anys provides a collection of matchers designed for pytest-style assertions, enabling more flexible comparisons in unit tests. Instead of strict equality checks, it allows developers to assert that values meet specific criteria (e.g., `ANY_DATETIME_STR` for any valid ISO 8601 timestamp string). This simplifies testing dynamic or partially unpredictable data structures. The library is actively maintained, with the current version being 0.3.1.

Warnings

gotcha When an `anys` matcher encounters a `TypeError` or `ValueError` during comparison (e.g., attempting to apply a regular expression matcher like `AnyMatch(r'\d+')` to an integer `42`), the library explicitly suppresses the exception and the comparison silently evaluates to `False`. This behavior, while intended, can mask unexpected type mismatches that might indicate a deeper issue if not anticipated.
Fix: Be explicit about the expected types when using matchers. If a type mismatch might be indicative of a bug, consider adding a separate `isinstance()` check or use matchers specifically designed for numeric types (e.g., `ANY_INT`, `AnyGT`).
gotcha Most `anys` class constructors (e.g., `AnyHas`, `AnyMapping`, `AnyDictOf`) are not designed to take other `anys` matchers as arguments for their keys or specific internal structures unless explicitly documented. Attempting to nest matchers in unsupported ways may lead to unexpected comparison results, `False` evaluations due to suppressed errors, or incorrect behavior.
Fix: Consult the `anys` documentation for each specific matcher to understand what types of arguments it accepts. For complex nested matching, ensure each level of matching is compatible with the parent matcher's design.

Install

pip install anys Install with pip

Imports

ANY_DATETIME_STR
```
from anys import ANY_DATETIME_STR
```
ANY_INT
```
from anys import ANY_INT
```
ANY_STR
```
from anys import ANY_STR
```
AnyGT
```
from anys import AnyGT
```
AnyLT
```
from anys import AnyLT
```
AnyMatch
```
from anys import AnyMatch
```
While technically possible, the documentation examples primarily use direct `from anys import ...` for brevity and clarity when using specific matchers.

Quickstart

This quickstart demonstrates how to use `anys` for flexible assertions, particularly with dynamic data like API responses. It uses `ANY_STR` to match any string and `ANY_DATETIME_STR` to match any valid ISO 8601 datetime string, allowing the test to pass even if the exact values for `id`, `created_at`, `status`, or `last_login` are not known in advance.

from anys import ANY_DATETIME_STR

def test_api_response():
    # Imagine this is a dynamic response from an API or function
    dynamic_data = {
        "id": "user-123",
        "name": "Test User",
        "created_at": "2024-04-12T10:30:00Z",
        "details": {
            "status": "active",
            "last_login": "2024-04-12T10:29:55Z"
        }
    }

    # Assert against a structure with matchers for dynamic fields
    expected_pattern = {
        "id": ANY_STR, # Match any string
        "name": "Test User",
        "created_at": ANY_DATETIME_STR, # Match any valid ISO datetime string
        "details": {
            "status": ANY_STR,
            "last_login": ANY_DATETIME_STR
        }
    }

    assert dynamic_data == expected_pattern
    print("Assertion successful: Dynamic data matches expected pattern!")

test_api_response()

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