add tests to maintain whitespace style constraints

.# Discussion

These tests help to maintain five style constraints:

1. files have no utf-8 byte-order-marks (BOM)
2. all files have CRLF EOLNs (*required* for correct operation of BAT/CMD script files)
3. all files end with a newline
4. any leading whitespace consists solely of spaces
5. no trailing whitespace

By using these constraints, whitespace noise between commits is reduced to a minimum.

test/00-Project.Tests.ps1

@@ -0,0 +1,126 @@
+$repo_dir = (Get-Item $MyInvocation.MyCommand.Path).directory.parent.FullName
+
+describe 'Project style constraints' {
+
+    $files = @(
+        # gather all files except '*.exe', '*.zip', or any .git repository files
+        Get-ChildItem $repo_dir -file -recurse -force | ? { $_.fullname -notmatch '(.git(|\\.*)|.exe|.zip)$' }
+    )
+
+    it 'files do not contain leading utf-8 BOM' {
+        # utf-8 BOM == 0xEF 0xBB 0xBF
+        # NOTE: utf-16LE BOM == 0xFF 0xFE; utf-16LE BOM == 0xFF 0xFE
+        # see http://www.powershellmagazine.com/2012/12/17/pscxtip-how-to-determine-the-byte-order-mark-of-a-text-file @@ https://archive.is/RgT42
+        # ref: http://poshcode.org/2153 @@ https://archive.is/sGnnu
+        # ref: http://www.johndcook.com/blog/powershell_perl_regex @@ https://archive.is/gHa60
+        $badFiles = @(
+            foreach ($file in $files)
+            {
+                $content = ([char[]](Get-Content $file.FullName -encoding byte -totalcount 3) -join '')
+                if ([regex]::match($content, '(?ms)^\xEF\xBB\xBF').success)
+                {
+                    $file.FullName
+                }
+            }
+        )
+
+        if ($badFiles.Count -gt 0)
+        {
+            throw "The following files have utf-8 BOM: `r`n`r`n$($badFiles -join "`r`n")"
+        }
+    }
+
+    it 'files all have line endings which are CRLF' {
+        # ref: http://www.johndcook.com/blog/powershell_perl_regex @@ https://archive.is/gHa60
+        $badFiles = @(
+            foreach ($file in $files)
+            {
+                $content = Get-Content -raw $file.FullName
+                $lines = [regex]::split($content, '\r\n')
+                $lineCount = $lines.Count
+
+                for ($i = 0; $i -lt $lineCount; $i++)
+                {
+                    if ( [regex]::match($lines[$i], '\r|\n').success )
+                    {
+                        $file.FullName
+                        break
+                    }
+                }
+            }
+        )
+
+        if ($badFiles.Count -gt 0)
+        {
+            throw "The following files have non-CRLF line endings: `r`n`r`n$($badFiles -join "`r`n")"
+        }
+    }
+
+    it 'files all end with a newline' {
+        $badFiles = @(
+            foreach ($file in $files)
+            {
+                $string = [System.IO.File]::ReadAllText($file.FullName)
+                if ($string.Length -gt 0 -and $string[-1] -ne "`n")
+                {
+                    $file.FullName
+                }
+            }
+        )
+
+        if ($badFiles.Count -gt 0)
+        {
+            throw "The following files do not end with a newline: `r`n`r`n$($badFiles -join "`r`n")"
+        }
+    }
+
+    it 'files have leading whitespace consisting only of spaces' {
+        $badLines = @(
+            foreach ($file in $files)
+            {
+                if ($file.fullname -notmatch 'makefile$')
+                {
+                    $lines = [System.IO.File]::ReadAllLines($file.FullName)
+                    $lineCount = $lines.Count
+
+                    for ($i = 0; $i -lt $lineCount; $i++)
+                    {
+                        if ($lines[$i] -notmatch '^[ ]*(\S|$)')
+                        {
+                            'File: {0}, Line: {1}' -f $file.FullName, ($i + 1)
+                        }
+                    }
+                }
+            }
+        )
+
+        if ($badLines.Count -gt 0)
+        {
+            throw "The following $($badLines.Count) lines contain TABs within leading whitespace: `r`n`r`n$($badLines -join "`r`n")"
+        }
+    }
+
+    it 'files have no lines containing trailing whitespace' {
+        $badLines = @(
+            foreach ($file in $files)
+            {
+                $lines = [System.IO.File]::ReadAllLines($file.FullName)
+                $lineCount = $lines.Count
+
+                for ($i = 0; $i -lt $lineCount; $i++)
+                {
+                    if ($lines[$i] -match '\s+$')
+                    {
+                        'File: {0}, Line: {1}' -f $file.FullName, ($i + 1)
+                    }
+                }
+            }
+        )
+
+        if ($badLines.Count -gt 0)
+        {
+            throw "The following $($badLines.Count) lines contain trailing whitespace: `r`n`r`n$($badLines -join "`r`n")"
+        }
+    }
+
+}