Assert-BlockString: Allow string array and single string for Expected

CHANGELOG.md

@@ -13,3 +13,5 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Updated README.md
+- `Assert-BlockString`
+  - Allow it to pass string array and single string to `Expected` parameter.

source/Public/Assert-BlockString.ps1

@@ -57,7 +57,6 @@ function Assert-BlockString
         $Actual,
 
         [Parameter(Position = 0, Mandatory = $true)]
-        [System.String[]]
         $Expected,
 
         [Parameter()]
@@ -77,19 +76,25 @@ function Assert-BlockString
     }
 
     # Verify if $Actual is a string or string array
-    $isStringType = $Actual -is [System.String] -or ($Actual -is [System.Array] -and $Actual[0] -is [System.String])
+    $isActualStringType = $Actual -is [System.String] -or ($Actual -is [System.Array] -and ($Actual.Count -eq 0 -or ($Actual.Count -gt 0 -and $Actual[0] -is [System.String])))
 
-    $stringsAreEqual = $isStringType -and (-join $Actual) -ceq (-join $Expected)
+    $isExpectedStringType = $Expected -is [System.String] -or ($Expected -is [System.Array] -and ($Expected.Count -eq 0 -or ($Expected.Count -gt 0 -and $Expected[0] -is [System.String])))
+
+    $stringsAreEqual = $isActualStringType -and $isExpectedStringType -and (-join $Actual) -ceq (-join $Expected)
 
     if (-not $stringsAreEqual)
     {
-        if (-not $isStringType)
+        if (-not $isActualStringType)
+        {
+            $message = 'The Actual value must be of type string or string[], but it was not.'
+        }
+        elseif (-not $isExpectedStringType)
         {
-            $message = 'Expected to actual value to be of type string or string[], but it was not.'
+            $message = 'The Expected value must be of type string or string[], but it was not.'
         }
         else
         {
-            $message = 'Expect the strings to be equal'
+            $message = 'Expected the strings to be equal'
 
             if ($Because)
             {

tests/Unit/Public/Assert-BlockString.tests.ps1

@@ -91,6 +91,46 @@ Describe 'Assert-BlockString' {
         { & $scriptBlock } | Should -Not -Throw
     }
 
+    It 'Should be able to pass empty collection as Expected' {
+        $mockExpected = 'Test string'
+
+        $scriptBlock = {
+            '' | Assert-BlockString -Expected @()
+        }
+
+        { & $scriptBlock } | Should -Not -Throw
+    }
+
+    It 'Should be able to pass empty string as Expected' {
+        $mockExpected = 'Test string'
+
+        $scriptBlock = {
+            '' | Assert-BlockString -Expected ''
+        }
+
+        { & $scriptBlock } | Should -Not -Throw
+    }
+
+    It 'Should be able to pass empty collection as Actual' {
+        $mockExpected = 'Test string'
+
+        $scriptBlock = {
+            Assert-BlockString -Actual @() -Expected @()
+        }
+
+        { & $scriptBlock } | Should -Not -Throw
+    }
+
+    It 'Should be able to pass empty string as Actual' {
+        $mockExpected = 'Test string'
+
+        $scriptBlock = {
+            Assert-BlockString -Actual '' -Expected ''
+        }
+
+        { & $scriptBlock } | Should -Not -Throw
+    }
+
     It 'Should be able to be called using its alias' {
         $mockExpected = 'Test string'
 
@@ -100,4 +140,24 @@ Describe 'Assert-BlockString' {
 
         { & $scriptBlock } | Should -Not -Throw
     }
+
+    It 'Should throw the correct error message when Actual is not a string' {
+        $mockExpected = 'Test string'
+
+        $scriptBlock = {
+            ([Int32] -1) | Should-BeBlockString -Expected $mockExpected
+        }
+
+        { & $scriptBlock } | Should -Throw -ExpectedMessage 'The Actual value must be of type string or string`[`], but it was not.'
+    }
+
+    It 'Should throw the correct error message when Expected is not a string' {
+        $mockActual = 'Test string'
+
+        $scriptBlock = {
+            'Test string' | Should-BeBlockString -Expected ([Int32] -1)
+        }
+
+        { & $scriptBlock } | Should-Throw -ExceptionMessage 'The Expected value must be of type string or string`[`], but it was not.'
+    }
 }