Voluble 0.1.5

Voluble

An open-sourced alternative to expressive assertions.

Notice - This library was made as a test to see how easy it was to create expressive assertions and a bit of jab at another library whom shall not be named. Consider using Shouldly, but feel free to test this library if you want to.

Definition

(adjective)
(of a person) talking fluently, readily, or incessantly.
"a voluble game-show host"
or.
an assertion library not costing 130$ per seat.

Installation

Dotnet-Cli

dotnet add package Voluble

Features

• Fluent assertion syntax with .Should() entry point
• Chainable assertions
• String assertions (contains, starts/ends with, regex matching, length)
• Numeric assertions (comparisons, ranges, sign, approximations)
• Collection assertions (contains, count, ordering, equivalence)
• DateTime assertions (before/after, components, day of week)
• Type assertions (exact type, assignability)
• Exception assertions (sync and async)
• Custom failure messages with because parameter
• VolubleScope for collecting multiple assertion failures

Usage

Basic Assertions

"hello".Should().Be("hello");
42.Should().NotBe(0);
myObject.Should().NotBeNull();

String Assertions

"hello world".Should().Contain("world");
"hello world".Should().StartWith("hello");
"hello world".Should().EndWith("world");
"hello world".Should().Match(@"hello \w+");
"hello".Should().HaveLength(5);
"".Should().BeNullOrEmpty();

Numeric Assertions

42.BeGreaterThan(0);
42.BeLessThanOrEqualTo(100);
42.BeInRange(1, 50);
3.14.BeApproximately(Math.PI, tolerance: 0.01);
(-5).BeNegative();
0.BeZero();

Collection Assertions

var list = new[] { 1, 2, 3 };
list.Contain(2);
list.NotContain(5);
list.HaveCount(3);
list.NotBeEmpty();
list.BeInAscendingOrder();
list.ContainSingle(x => x > 2);
list.BeEquivalentTo(new[] { 3, 1, 2 }); // order independent

DateTime Assertions

DateTime.Now.BeAfter(DateTime.MinValue);
DateTime.Now.BeOnWeekday();
someDate.HaveYear(2025);
someDate.BeCloseTo(expectedDate, TimeSpan.FromSeconds(1));

Exception Assertions

Action act = () => throw new InvalidOperationException();
act.Should().Throw<InvalidOperationException>();

Func<Task> asyncAct = async () => await FailingMethodAsync();
await asyncAct.Should().ThrowAsync<InvalidOperationException>();

Type Assertions

object obj = "hello";
obj.Should().BeOfType<string>();
obj.Should().BeAssignableTo<IEnumerable<char>>();

Custom Failure Messages

price.Should().Be(0, because: "the cart is empty");

VolubleScope - Collect Multiple Failures

By default, assertions fail immediately. Use VolubleScope to collect all failures and report them together at the end:

using (new VolubleScope())
{
    1.Should().Be(2);  // collected, doesn't throw yet
    "a".Should().Be("b");  // collected
}  // throws here with all failures

Requirements

• .NET 9.0 or .NET 10.0

License

Apache 2.0