Misc fixes related to json schema validation

Author: adityapatwardhan

src/dsc/psresourceget.ps1

@@ -82,11 +82,14 @@ class PSResource {
     }
 
     [string] ToJson() {
-        return ($this | Select-Object -ExcludeProperty _inDesiredState | ConvertTo-Json -Compress)
+        $retVal = ($this | Select-Object -ExcludeProperty _inDesiredState | ConvertTo-Json -Compress -EnumsAsStrings)
+        Write-Trace -message "Serializing PSResource to JSON. Name: $($this.name), Version: $($this.version), Scope: $($this.scope), RepositoryName: $($this.repositoryName), PreRelease: $($this.preRelease), _exist: $($this._exist)" -level trace
+        Write-Trace -message "Serialized JSON: $retVal" -level trace
+        return $retVal
     }
 
     [string] ToJsonForTest() {
-        return ($this | ConvertTo-Json -Compress -Depth 5)
+        return ($this | ConvertTo-Json -Compress -Depth 5 -EnumsAsStrings)
     }
 }
 
@@ -140,12 +143,17 @@ class PSResourceList {
         $resourceJson = "[$resourceJson]"
         $jsonString = "{'repositoryName': '$($this.repositoryName)','resources': $resourceJson}"
         $jsonString = $jsonString -replace "'", '"'
-        return $jsonString | ConvertFrom-Json | ConvertTo-Json -Compress
+        $retVal =  $jsonString | ConvertFrom-Json | ConvertTo-Json -Compress -EnumsAsStrings
+
+        Write-Trace -message "Serializing PSResourceList to JSON. RepositoryName: $($this.repositoryName), TrustedRepository: $($this.trustedRepository), Resources count: $($this.resources.Count)" -level trace
+        Write-Trace -message "Serialized JSON: $retVal" -level trace
+
+        return $retVal
     }
 
     [string] ToJsonForTest() {
         Write-Trace -message "Serializing PSResourceList to JSON for test output. RepositoryName: $($this.repositoryName), TrustedRepository: $($this.trustedRepository), Resources count: $($this.resources.Count)" -level trace
-        $jsonForTest = $this | ConvertTo-Json -Compress -Depth 5
+        $jsonForTest = $this | ConvertTo-Json -Compress -Depth 5 -EnumsAsStrings
         Write-Trace -message "Serialized JSON: $jsonForTest" -level trace
         return $jsonForTest
     }
@@ -162,6 +170,7 @@ class Repository {
     Repository([string]$name) {
         $this.name = $name
         $this._exist = $false
+        $this.repositoryType = 'Unknown'
     }
 
     Repository([string]$name, [string]$uri, [bool]$trusted, [int]$priority, [string]$repositoryType) {
@@ -185,10 +194,11 @@ class Repository {
     Repository([string]$name, [bool]$exist) {
         $this.name = $name
         $this._exist = $exist
+        $this.repositoryType = 'Unknown'
     }
 
     [string] ToJson() {
-        return ($this | ConvertTo-Json -Compress)
+        return ($this | ConvertTo-Json -Compress -EnumsAsStrings)
     }
 }
 

src/dsc/psresourcelist.dsc.resource.json

@@ -92,7 +92,7 @@
         "repositoryName": {
           "title": "Repository Name",
           "description": "The name of the repository from where the resources are acquired.",
-          "type": "string"
+          "type": ["string", "null"]
         },
         "trustedRepository": {
           "title": "Trusted Repository",
@@ -115,7 +115,7 @@
       },
       "$defs": {
         "Scope": {
-          "type": "string",
+          "type": ["string", "null"],
           "title": "Scope",
           "description": "Scope of the resource installation.",
           "enum": [
@@ -133,12 +133,12 @@
             "name": {
               "title": "Name",
               "description": "The name of the resource.",
-              "type": "string"
+              "type": ["string", "null"]
             },
             "version": {
               "title": "Version",
               "description": "The version range of the resource.",
-              "type": "string"
+              "type": ["string", "null"]
             },
             "scope": {
               "title": "Scope",
@@ -148,7 +148,7 @@
             "repositoryName": {
               "title": "Repository Name",
               "description": "The name of the repository from where the resource is acquired.",
-              "type": "string"
+              "type": ["string", "null"]
             },
             "preRelease": {
               "title": "Pre-Release version",

src/dsc/repository.dsc.resource.json

@@ -100,7 +100,7 @@
                 "uri": {
                     "title": "URI",
                     "description": "The URI of the repository.",
-                    "type": "string",
+                    "type": ["string", "null"],
                     "format": "uri"
                 },
                 "trusted": {