fluent-asserts

From This

assert(user.age > 18);
// Assertion failure: false is not true

To This

expect(user.age).to.be.greaterThan(18);
// ASSERTION FAILED: expect(user.age) should be greater than 18
//   ACTUAL: 16
//   EXPECTED: greater than 18

The difference is clarity. When tests fail at 2am, you need to understand why immediately. fluent-asserts gives you assertions that read like sentences and error messages that tell you exactly what went wrong.

---

The Fluent Chain

Every assertion flows naturally from value to expectation:

expect(response.status)    // what you're testing
    .to.be                 // optional readability
    .greaterOrEqualTo(200);// the assertion

The language chains (.to, .be) improve readability—they exist purely so your tests read like documentation.

---

Beyond Values

Test behavior, not just data:

// Memory allocation
expect({ auto arr = new int[1000]; })
    .to.allocateGCMemory();

// Exceptions
expect({ parseConfig("invalid"); })
    .to.throwException!ConfigError
    .withMessage("Invalid syntax");

// Execution time
expect({ complexCalculation(); })
    .to.haveExecutionTime
    .lessThan(100.msecs);

---

Quick Example

import fluent.asserts;

unittest {
    expect("hello").to.equal("hello");
    expect(42).to.be.greaterThan(10);
    expect([1, 2, 3]).to.contain(2);
    expect(10).to.not.equal(20);
}