Assert Package

The Assert built-in package supplies the assertion functions used to write unit tests for twinBASIC code. Each assertion checks an expected condition; on failure, it records a test failure with the call site and an optional message. The test runner --- the twinBASIC IDE's Test Explorer, or any equivalent harness --- collects those results, decides which tests passed, failed, or were skipped, and reports them.

The package's three modules --- Exact, Strict, and Permissive --- expose the same fifteen assertion functions; only the comparison semantics differ. Each flavour matches a different strictness level for equality evaluation.

Module	String comparisons	Numeric and other comparisons
Exact	case-sensitive	no implicit conversions; datatypes must match exactly (5 ≠ 5.0); vbNullString is distinct from ""; Empty is distinct from 0, False, and ""; object default members are not evaluated
Strict	case-sensitive	evaluated as if the comparison were written directly in twinBASIC code; object default members are not evaluated
Permissive	case-insensitive	evaluated as if the comparison were written directly in twinBASIC code

Null is never considered equal to anything --- not even to itself --- under any of the three flavours. To test for Null explicitly, use the IsNull / IsNotNull assertions rather than AreEqual(..., Null).

Sub TestStringReverse()
    Strict.AreEqual "olleh", StrReverse("hello")
    Strict.AreEqual "", StrReverse("")
End Sub

Calling convention

Every member of every module is tagged [MustBeQualified(True)] --- calls must be written with the module name, even from inside a project that has imported the Assert package:

Strict.IsTrue x > 0          ' OK
IsTrue x > 0                 ' compile error — module qualifier required

If a project references more than one package that exposes a module called Strict, qualify further with the package name as well: Assert.Strict.IsTrue x.

Debug-only

Every assertion is tagged [DebugOnly(True)] --- the calls compile to nothing in release builds, in the same way that Debug.Print and the Debug.Assert statement do. A test runner therefore needs to build the project with debug enabled.

Modules

• Exact -- strictest comparisons; datatypes must match and conversions never happen
• Strict -- case-sensitive strings, but otherwise equality matches a direct comparison in twinBASIC code
• Permissive -- case-insensitive strings; otherwise equality matches a direct comparison in twinBASIC code

Members

Each module exposes the same fifteen functions, grouped here by purpose:

• Diagnostic outcome --- Succeed, Fail, Inconclusive
• Equality --- AreEqual / AreNotEqual, AreSame / AreNotSame
• Boolean --- IsTrue, IsFalse
• Reference and value state --- IsNothing / IsNotNothing, IsNull / IsNotNull
• Sequence --- SequenceEquals / NotSequenceEquals

See the per-module pages for the full signatures and the comparison semantics that apply to each member.