refactor(cmd_available/Get-Command): Add Test-CommandAvailable function

lib/buckets.ps1

@@ -68,9 +68,8 @@ function add_bucket($name, $repo) {
         if (!$repo) { "Unknown bucket '$name'. Try specifying <repo>."; $usage_add; exit 1 }
     }
 
-    $git = try { Get-Command 'git' -ea stop } catch { $null }
-    if (!$git) {
-        abort "Git is required for buckets. Run 'scoop install git'."
+    if (!(Test-CommandAvailable git)) {
+        abort "Git is required for buckets. Run 'scoop install git' and try again."
     }
 
     $dir = bucketdir $name

lib/core.ps1

@@ -152,6 +152,13 @@ function file_path($app, $file) {
     return $null
 }
 
+Function Test-CommandAvailable {
+    Param (
+        [String]$Name
+    )
+    Return [Boolean](Get-Command $Name -ErrorAction Ignore)
+}
+
 function 7zip_path() {
     return (file_path '7zip' '7z.exe')
 }
@@ -486,7 +493,7 @@ function ensure_scoop_in_path($global) {
 }
 
 function ensure_robocopy_in_path {
-    if(!(Get-Command robocopy -ea ignore)) {
+    if(!(Test-CommandAvailable robocopy)) {
         shim "C:\Windows\System32\Robocopy.exe" $false
     }
 }

lib/diagnostic.ps1

@@ -9,8 +9,7 @@ function check_windows_defender($global) {
     $defender = get-service -name WinDefend -errorAction SilentlyContinue
     if($defender -and $defender.status) {
         if($defender.status -eq [system.serviceprocess.servicecontrollerstatus]::running) {
-            $hasGetMpPreference = Get-Command get-mppreference -errorAction SilentlyContinue
-            if($hasGetMpPreference) {
+            if (Test-CommandAvailable Get-MpPreference) {
                 $installPath = $scoopdir;
                 if($global) { $installPath = $globaldir; }
 

lib/install.ps1

@@ -666,7 +666,7 @@ function check_hash($file, $hash, $app_name) {
 
 function compute_hash($file, $algname) {
     try {
-        if([bool](Get-Command -Name Get-FileHash -ErrorAction SilentlyContinue) -eq $true) {
+        if(Test-CommandAvailable Get-FileHash) {
             return (Get-FileHash -Path $file -Algorithm $algname).Hash.ToLower()
         } else {
             $fs = [system.io.file]::openread($file)
@@ -683,11 +683,6 @@ function compute_hash($file, $algname) {
     return ''
 }
 
-function cmd_available($cmd) {
-    try { Get-Command $cmd -ea stop | out-null } catch { return $false }
-    $true
-}
-
 # for dealing with installers
 function args($config, $dir, $global) {
     if($config) { return $config | ForEach-Object { (format $_ @{'dir'=$dir;'global'=$global}) } }

libexec/scoop-update.ps1

@@ -52,8 +52,7 @@ if (!$branch) {
 
 function update_scoop() {
     # check for git
-    $git = try { Get-Command git -ea stop } catch { $null }
-    if(!$git) { abort "Scoop uses Git to update itself. Run 'scoop install git' and try again." }
+    if(!(Test-CommandAvailable git)) { abort "Scoop uses Git to update itself. Run 'scoop install git' and try again." }
 
     write-host "Updating Scoop..."
     $last_update = $(last_scoop_update)

libexec/scoop-which.ps1

@@ -12,7 +12,7 @@ if(!$command) { 'ERROR: <command> missing'; my_usage; exit 1 }
 try {
     $gcm = Get-Command "$command" -ea stop
 } catch {
-    [console]::error.writeline("'$command' not found"); exit 3
+    abort "'$command' not found" 3
 }
 
 $path = "$($gcm.path)"

test/Scoop-Core.Tests.ps1

@@ -135,12 +135,6 @@ Describe "get_app_name_from_ps1_shim" -Tag 'Scoop' {
         get_app_name_from_ps1_shim "$shim_path" | should -be "mockapp"
     }
 
-    It "returns app name if file exists and is a shim to an app cerca August 2018" -skip:$isUnix {
-        Write-Output '$path = join-path "$psscriptroot" "..\apps\vim\current\vim.exe"' | Out-File "$working_dir/moch-shim.ps1" -Encoding utf8
-        Write-Output 'if($myinvocation.expectingInput) { $input | & $path  @args } else { & $path  @args }' | Out-File "$working_dir/moch-shim.ps1" -Append -Encoding utf8
-        get_app_name_from_ps1_shim "$working_dir/moch-shim.ps1" | should -be "vim"
-    }
-
     It "returns empty string if file exists and is not a shim" -skip:$isUnix {
         Write-Output "lorem ipsum" | Out-File -Encoding ascii "$working_dir/mock-shim.ps1"
         get_app_name_from_ps1_shim "$working_dir/mock-shim.ps1" | should -be ""
@@ -165,8 +159,8 @@ describe "ensure_robocopy_in_path" -Tag 'Scoop' {
 
     context "robocopy is not in path" {
         it "shims robocopy when not on path" -skip:$isUnix {
-            mock gcm { $false }
-            Get-Command robocopy | should -be $false
+            mock Test-CommandAvailable { $false }
+            Test-CommandAvailable robocopy | should -be $false
 
             ensure_robocopy_in_path
 
@@ -180,7 +174,9 @@ describe "ensure_robocopy_in_path" -Tag 'Scoop' {
 
     context "robocopy is in path" {
         it "does not shim robocopy when it is in path" -skip:$isUnix {
-            mock gcm { $true }
+            mock Test-CommandAvailable { $true }
+            Test-CommandAvailable robocopy | should -be $true
+
             ensure_robocopy_in_path
 
             "$shimdir/robocopy.ps1" | should -not -exist