Table of Contents

Ploch.TestingSupport.FluentAssertions

Custom FluentAssertions extensions for string and reflection assertions.

Overview

Ploch.TestingSupport.FluentAssertions extends the FluentAssertions library with assertion methods that are not part of the standard FluentAssertions distribution. It currently provides two areas of functionality:

  • String assertions — ContainAllEquivalentOf asserts that a string contains every one of a supplied list of substrings, using a case-insensitive comparison. This fills a gap in the standard StringAssertions API, which only exposes ContainEquivalentOf for a single expected substring at a time.
  • Reflection / property assertions — PropertyInfoCollectionAssertions (exposed via PropertyInfoCollectionExtensions.Should()) adds ContainProperty and ContainProperties assertions on IEnumerable<PropertyInfo> collections. These are useful when verifying that a type exposes specific properties, for example in tests for mapping configurations or serialisation contracts.

The library targets netstandard2.0 and depends on FluentAssertions, Ploch.Common, and TestableIO.System.IO.Abstractions.

Installation

dotnet add package Ploch.TestingSupport.FluentAssertions

Key Types

Type Description
StringAssertionExtensions Static class. Adds ContainAllEquivalentOf(params string?[] values) and its IEnumerable<string?> overload to StringAssertions.
PropertyInfoCollectionExtensions Static class. Adds Should() to IEnumerable<PropertyInfo>, returning a PropertyInfoCollectionAssertions.
PropertyInfoCollectionAssertions Extends GenericCollectionAssertions<PropertyInfo> with ContainProperty(string, object) and ContainProperties(string[], object).

Usage Examples

Asserting a string contains multiple substrings (case-insensitive)

var message = "Order confirmed for customer John, total: 99.99";

message.Should().ContainAllEquivalentOf("ORDER", "customer", "John", "99.99");

Failure output identifies which substrings were missing:

Expected string "Order confirmed for customer John, total: 99.99"
to contain the strings ignoring case: ["shipping", "discount"]
but ["shipping", "discount"] was not found.

You can also pass an enumerable and supply a because clause:

var requiredTokens = new[] { "status", "active" };

responseBody.Should().ContainAllEquivalentOf(
    requiredTokens,
    because: "the API response must include status information");

Asserting property presence on a type

ContainProperty and ContainProperties work on the result of reflecting a type's GetProperties() call. They look up the actual PropertyInfo on the supplied sourceObj's type to ensure that the property name resolves correctly.

var dto = new UserDto { Name = "Alice", Email = "alice@example.com" };
var properties = typeof(UserDto).GetProperties();

properties.Should().ContainProperty("Name", dto);
properties.Should().ContainProperties(new[] { "Name", "Email" }, dto);
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