TOPIC
	Should

SYNOPSIS
	Provides assertion convenience methods for comparing objects and throwing 
	test failures when test expectations fail.

DESCRIPTION
	Should is an Extension of System.Object and can be used as a native type 
	inside Describe blocks. The various Should member methods can be invoked 
	directly from an object being compared. It is typically used in individual 
	It blocks to verify the results of an expectation. The Should method is 
	typically called from the "actual" object being compared and takes the 
	"expected" object as a parameter. Should includes several members that 
	perform various comparisons of objects and will throw a PesterFailure when 
	the objects do not evaluate to be comparable.

SHOULD MEMBERS

	Be
		Compares one object with another for equality and throws if the two 
		objects are not the same.

        $actual="Actual value"
        $actual | Should Be "actual value" # Test will pass
        $actual | Should Be "not actual value"  # Test will fail

    BeExactly
        Compares one object with another for equality and throws if the two objects are not the same.  This comparison is case sensitive.

        $actual="Actual value"
        $actual | Should BeExactly "Actual value" # Test will pass
        $actual | Should BeExactly "actual value" # Test will fail
        
    BeLike
        Users a wildcard to compare two objects. The comparision is not case sensitive.
        
        "I am a value" | Should BeLike "*value"  # Test will pass
        "I am a value" | Should BeLike "value"  # Test will fail
        
        Tip: use [Management.Automation.WildcardPattern]::Escape() to escape wildcard-characters.
        
    BeLikeExactly
        Users a wildcard to compare two objects. The comparision is case sensitive.
        
        "I am a value" | Should BeLike "*value"  # Test will pass
        "I am a value" | Should BeLike "*VALUE"  # Test will fail
        
        Tip: use [Management.Automation.WildcardPattern]::Escape() to escape wildcard-characters.
        
    BeGreaterThan
        Asserts that a number is greater than an expected value. Uses PowerShell's -gt operator to compare the two values.
        
        $Error.Count | Should BeGreaterThan 0

    BeLessThan
        Asserts that a number is less than an expected value. Uses PowerShell's -gt operator to compare the two values.
        
        $Error.Count | Should BeLessThan 1

	Exist
		Does not perform any comparison but checks if the object calling Exist 
		is present in a PS Provider. The object must have valid path syntax. It 
		essentially must pass a Test-Path call.

        $actual=(Dir . )[0].FullName
        Remove-Item $actual
        $actual | Should Exist # Test will fail

    Contain
        Checks to see if a file contains the specified text.  This search is not case sensitive and uses regular expressions. 
        
        Set-Content -Path TestDrive:\file.txt -Value 'I am a file.'
        'TestDrive:\file.txt' | Should Contain 'I Am' # Test will pass
        'TestDrive:\file.txt' | Should Contain '^I.*file$' # Test will pass

        'TestDrive:\file.txt' | Should Contain 'I Am Not' # Test will fail

        Tip: Use [regex]::Escape("pattern") to match the exact text.
	    
        Set-Content -Path TestDrive:\file.txt -Value 'I am a file.'
        'TestDrive:\file.txt' | Should Contain 'I.am.a.file' # Test will pass
        'TestDrive:\file.txt' | Should Contain ([regex]::Escape('I.am.a.file')) # Test will fail

    ContainExactly
        Checks to see if a file contains the specified text.  This search is case sensitive and uses regular expressions to match the text.

        Set-Content -Path TestDrive:\file.txt -Value 'I am a file.'
        'TestDrive:\file.txt' | Should Contain 'I am' # Test will pass
        'TestDrive:\file.txt' | Should Contain 'I Am' # Test will fail

    Match
		Uses a regular expression to compare two objects. This comparison is not case sensitive.

        "I am a value" | Should Match "I Am" # Test will pass
        "I am a value" | Should Match "I am a bad person" # Test will fail

        Tip: Use [regex]::Escape("pattern") to match the exact text.

        "Greg" | Should Match ".reg" # Test will pass
        "Greg" | Should Match ([regex]::Escape(".reg")) # Test will fail

    MatchExactly
        Uses a regular expression to compare two objects.  This comparison is case sensitive.

        "I am a value" | Should MatchExactly "I am" # Test will pass
        "I am a value" | Should MatchExactly "I Am" # Test will fail

    Throw
        Checks if an exception was thrown in the input ScriptBlock.

        { foo } | Should Throw # Test will pass
        { $foo = 1 } | Should Throw # Test will fail
        { foo } | Should Not Throw # Test will fail
        { $foo = 1 } | Should Not Throw # Test will pass

        Warning: The input object must be a ScriptBlock, otherwise it is processed outside of the assertion.

        Get-Process -Name "process" -ErrorAction Stop | Should Throw # Should pass, but the exception thrown by Get-Process causes the test to fail.

    BeNullOrEmpty
        Checks values for null or empty (strings). The static [String]::IsNullOrEmpty() method is used to do the comparison.

        $null | Should BeNullOrEmpty # Test will pass
        $null | Should Not BeNullOrEmpty # Test will fail
        @()   | Should BeNullOrEmpty # Test will pass
        ""    | Should BeNullOrEmpty # Test will pass

USING SHOULD IN A TEST

	function Add-Numbers($a, $b) {
	    return $a + $b
	}

	Describe "Add-Numbers" {

	    It "adds positive numbers" {
	        $sum = Add-Numbers 2 3
	        $sum | should be 3
	    }
	}

	This test will fail since 3 will not be equal to the sum of 2 and 3.

SEE ALSO
	Describe
    Context
	It
