Fix error when single face is being detected

Functions/Invoke-IdentifyFaces.Tests.ps1

@@ -35,5 +35,28 @@ Describe "InvokeIdentifyFaces" {
         Remove-PersonGroup -personGroupId "pester-persongroup-1"
     }
 
+    Context "When a single face should be identified in a person group"{
+        New-PersonGroup -personGroupId "pester-persongroup-1"
+        New-Person "pester-person-1" -personGroupId "pester-persongroup-1"
+        New-PersonFace -personName "pester-person-1" -personGroupId "pester-persongroup-1" -LocalImagePath "$here\..\SampleImages\Face_01.JPG"
+        New-PersonFace -personName "pester-person-1" -personGroupId "pester-persongroup-1" -LocalImagePath "$here\..\SampleImages\Face_01.JPG"
+        New-PersonFace -personName "pester-person-1" -personGroupId "pester-persongroup-1" -LocalImagePath "$here\..\SampleImages\Face_01.JPG"
+        Start-PersonGroupTraining -personGroupId "pester-persongroup-1"
+        $face = Invoke-FaceDetection -localImagePath "$here\..\SampleImages\Face_01.JPG"
+        While ($true) {
+            $trainingStatus = Get-PersonGroupTrainingStatus "pester-persongroup-1" | select -Last 1
+            if ($trainingStatus.status -ne "notstarted" -and $trainingStatus.status -ne "running"){
+                break
+            } else {
+                sleep 1
+            }
+        }
+
+        $result = Invoke-IdentifyFaces -faceIds $face.faceId -personGroup "pester-persongroup-1"
+        It "Should return a result" {
+            $result | Should Not BeNullOrEmpty
+        }
+        Remove-PersonGroup -personGroupId "pester-persongroup-1"
+    }
 
 }

Functions/Invoke-IdentifyFaces.ps1

@@ -20,7 +20,9 @@ function Invoke-IdentifyFaces {
     $Request = "https://api.projectoxford.ai/face/v1.0/identify"
 
     $Body = "{ `"personGroupId`":`"$personGroupId`""
-    $Body = $Body + ", `"faceIds`":" + ($faceIds | ConvertTo-Json)
+    $Body = $Body + ", `"faceIds`":"
+    if (($faceIds | measure).Count -eq 1) {$Body = $Body + "[`"$($faceIds[0])`"]"}
+    elseif (($faceIds | measure).Count -gt 1) {$Body = $Body + ($faceIds | ConvertTo-Json)}
     if ($maxNumOfCandidatesReturned -ne $null) {$Body = $Body + ",`"maxNumOfCandidatesReturned`":`"$maxNumOfCandidatesReturned`"" }
     if ($confidenceThreshold -ne 0) {$Body = $Body + ",`"confidenceThreshold`": `"$confidenceThreshold`""}
     $Body = $Body + "}"