@@ -125,7 +125,7 @@ Function Nuke-Everything {

     try {

-        if ($env:SKIP_ALL_CLEANUP -eq $null) {

+        if ($null -eq $env:SKIP_ALL_CLEANUP) {

             Write-Host -ForegroundColor green "INFO: Nuke-Everything..."

             $containerCount = ($(docker ps -aq | Measure-Object -line).Lines) 

             if (-not $LastExitCode -eq 0) {

@@ -160,11 +160,11 @@ Function Nuke-Everything {

             Stop-Process -Id $p -Force -ErrorAction SilentlyContinue

         }

-        if ($pidFile -ne $Null) {

+        if ($null -ne $pidFile) {

             Write-Host "INFO: Tidying pidfile $pidfile"

              if (Test-Path $pidFile) {

                 $p=Get-Content $pidFile -raw

-                if ($p -ne $null){

+                if ($null -ne $p){

                     Write-Host -ForegroundColor green "INFO: Stopping possible daemon pid $p"

                     taskkill -f -t -pid $p

                 }

@@ -190,7 +190,7 @@ Function Nuke-Everything {

         # Delete the directory using our dangerous utility unless told not to

         if (Test-Path "$env:TESTRUN_DRIVE`:\$env:TESTRUN_SUBDIR") {

-            if (($env:SKIP_ZAP_DUT -ne $null) -or ($env:SKIP_ALL_CLEANUP -eq $null)) {

+            if (($null -ne $env:SKIP_ZAP_DUT) -or ($null -eq $env:SKIP_ALL_CLEANUP)) {

                 Write-Host -ForegroundColor Green "INFO: Nuking $env:TESTRUN_DRIVE`:\$env:TESTRUN_SUBDIR"

                 docker-ci-zap "-folder=$env:TESTRUN_DRIVE`:\$env:TESTRUN_SUBDIR"

             } else {

@@ -256,25 +256,25 @@ Try {

     Get-ChildItem Env: | Out-String

     # PR

-    if (-not ($env:PR -eq $Null)) { echo "INFO: PR#$env:PR (https://github.com/docker/docker/pull/$env:PR)" }

+    if (-not ($null -eq $env:PR)) { echo "INFO: PR#$env:PR (https://github.com/docker/docker/pull/$env:PR)" }

     # Make sure docker is installed

-    if ((Get-Command "docker" -ErrorAction SilentlyContinue) -eq $null) { Throw "ERROR: docker is not installed or not found on path" }

+    if ($null -eq (Get-Command "docker" -ErrorAction SilentlyContinue)) { Throw "ERROR: docker is not installed or not found on path" }

     # Make sure docker-ci-zap is installed

-    if ((Get-Command "docker-ci-zap" -ErrorAction SilentlyContinue) -eq $null) { Throw "ERROR: docker-ci-zap is not installed or not found on path" }

+    if ($null -eq (Get-Command "docker-ci-zap" -ErrorAction SilentlyContinue)) { Throw "ERROR: docker-ci-zap is not installed or not found on path" }

     # Make sure SOURCES_DRIVE is set

-    if ($env:SOURCES_DRIVE -eq $Null) { Throw "ERROR: Environment variable SOURCES_DRIVE is not set" }

+    if ($null -eq $env:SOURCES_DRIVE) { Throw "ERROR: Environment variable SOURCES_DRIVE is not set" }

     # Make sure TESTRUN_DRIVE is set

-    if ($env:TESTRUN_DRIVE -eq $Null) { Throw "ERROR: Environment variable TESTRUN_DRIVE is not set" }

+    if ($null -eq $env:TESTRUN_DRIVE) { Throw "ERROR: Environment variable TESTRUN_DRIVE is not set" }

     # Make sure SOURCES_SUBDIR is set

-    if ($env:SOURCES_SUBDIR -eq $Null) { Throw "ERROR: Environment variable SOURCES_SUBDIR is not set" }

+    if ($null -eq $env:SOURCES_SUBDIR) { Throw "ERROR: Environment variable SOURCES_SUBDIR is not set" }

     # Make sure TESTRUN_SUBDIR is set

-    if ($env:TESTRUN_SUBDIR -eq $Null) { Throw "ERROR: Environment variable TESTRUN_SUBDIR is not set" }

+    if ($null -eq $env:TESTRUN_SUBDIR) { Throw "ERROR: Environment variable TESTRUN_SUBDIR is not set" }

     # SOURCES_DRIVE\SOURCES_SUBDIR must be a directory and exist

     if (-not (Test-Path -PathType Container "$env:SOURCES_DRIVE`:\$env:SOURCES_SUBDIR")) { Throw "ERROR: $env:SOURCES_DRIVE`:\$env:SOURCES_SUBDIR must be an existing directory" }

@@ -420,7 +420,7 @@ Try {

     New-Item -ItemType Directory "$env:TEMP\localappdata" -ErrorAction SilentlyContinue | Out-Null

     New-Item -ItemType Directory "$env:TEMP\binary" -ErrorAction SilentlyContinue | Out-Null

     New-Item -ItemType Directory "$env:TEMP\installer" -ErrorAction SilentlyContinue | Out-Null

-    if ($env:SKIP_COPY_GO -eq $null) {

+    if ($null -eq $env:SKIP_COPY_GO) {

         # Wipe the previous version of GO - we're going to get it out of the image

         if (Test-Path "$env:TEMP\go") { Remove-Item "$env:TEMP\go" -Recurse -Force -ErrorAction SilentlyContinue | Out-Null }

         New-Item -ItemType Directory "$env:TEMP\go" -ErrorAction SilentlyContinue | Out-Null

@@ -435,15 +435,15 @@ Try {

     # As of go 1.11, Dockerfile changed to be in the format like "FROM golang:1.11.0 AS base".

     # If a version number ends with .0 (as in 1.11.0, a convention used in golang docker

     # image versions), it needs to be removed (i.e. "1.11.0" becomes "1.11").

-    if ($goVersionDockerfile -eq $Null) {

+    if ($null -eq $goVersionDockerfile) {

         $goVersionDockerfile=$(Get-Content ".\Dockerfile" | Select-String "^FROM golang:")

-        if ($goVersionDockerfile -ne $Null) {

+        if ($null -ne $goVersionDockerfile) {

             $goVersionDockerfile = $goVersionDockerfile.ToString().Split(" ")[1].Split(":")[1] -replace '\.0$',''

         }

     } else {

         $goVersionDockerfile = $goVersionDockerfile.ToString().Split(" ")[2]

     }

-    if ($goVersionDockerfile -eq $Null) {

+    if ($null -eq $goVersionDockerfile) {

         Throw "ERROR: Failed to extract golang version from Dockerfile"

     }

     Write-Host  -ForegroundColor Green "INFO: Validating GOLang consistency in Dockerfile.windows..."

@@ -452,7 +452,7 @@ Try {

     }

     # Build the image

-    if ($env:SKIP_IMAGE_BUILD -eq $null) {

+    if ($null -eq $env:SKIP_IMAGE_BUILD) {

         Write-Host  -ForegroundColor Cyan "`n`nINFO: Building the image from Dockerfile.windows at $(Get-Date)..."

         Write-Host

         $ErrorActionPreference = "SilentlyContinue"

@@ -478,7 +478,7 @@ Try {

     }

     # Build the binary in a container unless asked to skip it.

-    if ($env:SKIP_BINARY_BUILD -eq $null) {

+    if ($null -eq $env:SKIP_BINARY_BUILD) {

         Write-Host  -ForegroundColor Cyan "`n`nINFO: Building the test binaries at $(Get-Date)..."

         $ErrorActionPreference = "SilentlyContinue"

         docker rm -f $COMMITHASH 2>&1 | Out-Null

@@ -530,7 +530,7 @@ Try {

     # Grab the golang installer out of the built image. That way, we know we are consistent once extracted and paths set,

     # so there's no need to re-deploy on account of an upgrade to the version of GO being used in docker.

-    if ($env:SKIP_COPY_GO -eq $null) {

+    if ($null -eq $env:SKIP_COPY_GO) {

         Write-Host -ForegroundColor Green "INFO: Copying the golang package from the container to $env:TEMP\installer\go.zip..."

         docker cp "$COMMITHASH`:c`:\go.zip" $env:TEMP\installer\

         if (-not($LastExitCode -eq 0)) {

@@ -593,7 +593,7 @@ Try {

     New-Item -ItemType Directory $env:TEMP\daemon -ErrorAction SilentlyContinue  | Out-Null

     # In LCOW mode, for now we need to set an environment variable before starting the daemon under test

-    if (($env:LCOW_MODE -ne $Null) -or ($env:LCOW_BASIC_MODE -ne $Null)) {

+    if (($null -ne $env:LCOW_MODE) -or ($null -ne $env:LCOW_BASIC_MODE)) {

         $env:LCOW_SUPPORTED=1

     }

@@ -606,13 +606,13 @@ Try {

     $daemonStarted=1

     # In LCOW mode, turn off that variable

-    if (($env:LCOW_MODE -ne $Null) -or ($env:LCOW_BASIC_MODE -ne $Null)) {

+    if (($null -ne $env:LCOW_MODE) -or ($null -ne $env:LCOW_BASIC_MODE)) {

         $env:LCOW_SUPPORTED=""

     }

     # Start tailing the daemon under test if the command is installed

-    if ((Get-Command "tail" -ErrorAction SilentlyContinue) -ne $null) { 

+    if ($null -ne (Get-Command "tail" -ErrorAction SilentlyContinue)) {

         $tail = start-process "tail" -ArgumentList "-f $env:TEMP\dut.out" -ErrorAction SilentlyContinue

     }

@@ -674,11 +674,11 @@ Try {

     Write-Host

     # Don't need Windows images when in LCOW mode.

-    if (($env:LCOW_MODE -eq $Null) -and ($env:LCOW_BASIC_MODE -eq $Null)) {

+    if (($null -eq $env:LCOW_MODE) -and ($null -eq $env:LCOW_BASIC_MODE)) {

         # Default to windowsservercore for the base image used for the tests. The "docker" image

         # and the control daemon use microsoft/windowsservercore regardless. This is *JUST* for the tests.

-        if ($env:WINDOWS_BASE_IMAGE -eq $Null) {

+        if ($null -eq $env:WINDOWS_BASE_IMAGE) {

             $env:WINDOWS_BASE_IMAGE="microsoft/windowsservercore"

         }

@@ -727,7 +727,7 @@ Try {

     }

     # Run the validation tests unless SKIP_VALIDATION_TESTS is defined.

-    if ($env:SKIP_VALIDATION_TESTS -eq $null) {

+    if ($null -eq $env:SKIP_VALIDATION_TESTS) {

         Write-Host -ForegroundColor Cyan "INFO: Running validation tests at $(Get-Date)..."

         $ErrorActionPreference = "SilentlyContinue"

         $Duration=$(Measure-Command { hack\make.ps1 -DCO -GoFormat -PkgImports | Out-Host })

@@ -742,8 +742,8 @@ Try {

     # Note the unit tests won't work in LCOW mode as I turned off loading the base images above.

     # Run the unit tests inside a container unless SKIP_UNIT_TESTS is defined

-    if (($env:LCOW_MODE -eq $Null) -and ($env:LCOW_BASIC_MODE -eq $Null)) {

-        if ($env:SKIP_UNIT_TESTS -eq $null) {

+    if (($null -eq $env:LCOW_MODE) -and ($null -eq $env:LCOW_BASIC_MODE)) {

+        if ($null -eq $env:SKIP_UNIT_TESTS) {

             Write-Host -ForegroundColor Cyan "INFO: Running unit tests at $(Get-Date)..."

             $ErrorActionPreference = "SilentlyContinue"

             $Duration=$(Measure-Command {docker run -e DOCKER_GITCOMMIT=$COMMITHASH$CommitUnsupported docker hack\make.ps1 -TestUnit | Out-Host })

@@ -758,8 +758,8 @@ Try {

     }

     # Add the Windows busybox image. Needed for WCOW integration tests

-    if (($env:LCOW_MODE -eq $Null) -and ($env:LCOW_BASIC_MODE -eq $Null)) {

-        if ($env:SKIP_INTEGRATION_TESTS -eq $null) {

+    if (($null -eq $env:LCOW_MODE) -and ($null -eq $env:LCOW_BASIC_MODE)) {

+        if ($null -eq $env:SKIP_INTEGRATION_TESTS) {

             $ErrorActionPreference = "SilentlyContinue"

             # Build it regardless while switching between nanoserver and windowsservercore

             #$bbCount = $(& "$env:TEMP\binary\docker-$COMMITHASH" "-H=$($DASHH_CUT)" images | Select-String "busybox" | Measure-Object -line).Lines

@@ -799,8 +799,8 @@ Try {

     }

     # Run the WCOW integration tests unless SKIP_INTEGRATION_TESTS is defined

-    if (($env:LCOW_MODE -eq $Null) -and ($env:LCOW_BASIC_MODE -eq $Null)) {

-        if ($env:SKIP_INTEGRATION_TESTS -eq $null) {

+    if (($null -eq $env:LCOW_MODE) -and ($null -eq $env:LCOW_BASIC_MODE)) {

+        if ($null -eq $env:SKIP_INTEGRATION_TESTS) {

             Write-Host -ForegroundColor Cyan "INFO: Running integration tests at $(Get-Date)..."

             $ErrorActionPreference = "SilentlyContinue"

@@ -810,7 +810,7 @@ Try {

             #https://blogs.technet.microsoft.com/heyscriptingguy/2011/09/20/solve-problems-with-external-command-lines-in-powershell/ is useful to see tokenising

             $c = "go test "

             $c += "`"-check.v`" "

-            if ($env:INTEGRATION_TEST_NAME -ne $null) { # Makes is quicker for debugging to be able to run only a subset of the integration tests

+            if ($null -ne $env:INTEGRATION_TEST_NAME) { # Makes is quicker for debugging to be able to run only a subset of the integration tests

                 $c += "`"-check.f`" "

                 $c += "`"$env:INTEGRATION_TEST_NAME`" "

                 Write-Host -ForegroundColor Magenta "WARN: Only running integration tests matching $env:INTEGRATION_TEST_NAME"

@@ -819,7 +819,7 @@ Try {

             $c += "`"-check.timeout`" " + "`"10m`" "

             $c += "`"-test.timeout`" " + "`"200m`" "

-            if ($env:INTEGRATION_IN_CONTAINER -ne $null) {

+            if ($null -ne $env:INTEGRATION_IN_CONTAINER) {

                 Write-Host -ForegroundColor Green "INFO: Integration tests being run inside a container"

                 # Note we talk back through the containers gateway address

                 # And the ridiculous lengths we have to go to to get the default gateway address... (GetNetIPConfiguration doesn't work in nanoserver)

@@ -853,7 +853,7 @@ Try {

         }

     } else {

         # The LCOW version of the tests here

-        if ($env:SKIP_INTEGRATION_TESTS -eq $null) {

+        if ($null -eq $env:SKIP_INTEGRATION_TESTS) {

             Write-Host -ForegroundColor Cyan "INFO: Running LCOW tests at $(Get-Date)..."

             $ErrorActionPreference = "SilentlyContinue"

@@ -868,7 +868,7 @@ Try {

             # Force to use the test binaries, not the host ones.

             $env:PATH="$env:TEMP\binary;$env:PATH;"  

-            if ($env:LCOW_BASIC_MODE -ne $null) {

+            if ($null -ne $env:LCOW_BASIC_MODE) {

                 $wc = New-Object net.webclient

                 try {

                     Write-Host -ForegroundColor green "INFO: Downloading latest execution script..."

@@ -891,7 +891,7 @@ Try {

                 #https://blogs.technet.microsoft.com/heyscriptingguy/2011/09/20/solve-problems-with-external-command-lines-in-powershell/ is useful to see tokenising

                 $c = "go test "

                 $c += "`"-check.v`" "

-                if ($env:INTEGRATION_TEST_NAME -ne $null) { # Makes is quicker for debugging to be able to run only a subset of the integration tests

+                if ($null -ne $env:INTEGRATION_TEST_NAME) { # Makes is quicker for debugging to be able to run only a subset of the integration tests

                     $c += "`"-check.f`" "

                     $c += "`"$env:INTEGRATION_TEST_NAME`" "

                     Write-Host -ForegroundColor Magenta "WARN: Only running LCOW integration tests matching $env:INTEGRATION_TEST_NAME"

@@ -935,7 +935,7 @@ Try {

     # Stop the daemon under test

     if (Test-Path "$env:TEMP\docker.pid") {

         $p=Get-Content "$env:TEMP\docker.pid" -raw

-        if (($p -ne $null) -and ($daemonStarted -eq 1)) {

+        if (($null -ne $p) -and ($daemonStarted -eq 1)) {

             Write-Host -ForegroundColor green "INFO: Stopping daemon under test"

             taskkill -f -t -pid $p

             #sleep 5

@@ -964,14 +964,14 @@ Finally {

     Write-Host  -ForegroundColor Green "INFO: Tidying up at end of run"

     # Restore the path

-    if ($origPath -ne $null) { $env:PATH=$origPath }

+    if ($null -ne $origPath) { $env:PATH=$origPath }

     # Restore the DOCKER_HOST

-    if ($origDOCKER_HOST -ne $null) { $env:DOCKER_HOST=$origDOCKER_HOST }

+    if ($null -ne $origDOCKER_HOST) { $env:DOCKER_HOST=$origDOCKER_HOST }

     # Restore the GOROOT and GOPATH variables

-    if ($origGOROOT -ne $null) { $env:GOROOT=$origGOROOT }

-    if ($origGOPATH -ne $null) { $env:GOPATH=$origGOPATH }

+    if ($null -ne $origGOROOT) { $env:GOROOT=$origGOROOT }

+    if ($null -ne $origGOPATH) { $env:GOPATH=$origGOPATH }

     # Dump the daemon log if asked to 

     if ($daemonStarted -eq 1) {