[CHANGED] we now preserve the environment variables during unit tests

[CHANGED] we now check that the default locations for the vendor locations are valid before using them
[CHANGED] we check that the DCC location exists AFTER making sure it is formatted correctly (slashes in correct directions)
[CHANGED] made safer the process during which we parse the given string from askMayaVersion()

Author: AJubrey

Assets/FbxExporters/Editor/FbxExportSettings.cs

@@ -264,14 +264,14 @@ private static string GetMayaLocationFromEnvironmentVariable(string env)
             if (string.IsNullOrEmpty(location))
                 return null;
 
-            if (!Directory.Exists(location))
-                return null;
-
             //Remove any extra slashes on the end
             //Maya would accept a single slash in either direction, so we should be able to
             location = location.Replace("\\", "/");
             location = location.TrimEnd('/');
 
+            if (!Directory.Exists(location))
+                return null;
+
             if (Application.platform == RuntimePlatform.WindowsEditor)
             {
                 //If we are on Windows, we need only go up one location to get to the "Autodesk" folder.                        
@@ -327,9 +327,32 @@ private static HashSet<string> GetCustomVendorLocations()
         private static HashSet<string> GetDefaultVendorLocations()
         {
             if (Application.platform == RuntimePlatform.WindowsEditor)
-                return new HashSet<string>() { "C:/Program Files/Autodesk", "D:/Program Files/Autodesk" };
+            {
+                HashSet<string> windowsDefaults = new HashSet<string>() { "C:/Program Files/Autodesk", "D:/Program Files/Autodesk" };
+                HashSet<string> existingDirectories = new HashSet<string>();
+                foreach (string path in windowsDefaults)
+                {
+                    if (Directory.Exists(path))
+                    {
+                        existingDirectories.Add(path);
+                    }
+                }
+                return existingDirectories;
+
+            }
             else if (Application.platform == RuntimePlatform.OSXEditor)
-                return new HashSet<string>() { "/Applications/Autodesk" };
+            {
+                HashSet<string> MacOSDefaults = new HashSet<string>() { "/Applications/Autodesk" };
+                HashSet<string> existingDirectories = new HashSet<string>();
+                foreach (string path in MacOSDefaults)
+                {
+                    if (Directory.Exists(path))
+                    {
+                        existingDirectories.Add(path);
+                    }
+                }
+                return existingDirectories;
+            }
 
             throw new NotImplementedException();
         }
@@ -807,10 +830,18 @@ static string AskMayaVersion(string exePath) {
             // Output is like: Maya 2018, Cut Number 201706261615
             // We want the stuff after 'Maya ' and before the comma.
             // (Uni-31601) less brittle! Consider also the mel command "about -version".
+            if (string.IsNullOrEmpty(resultString))
+            {
+                return null;
+            }
+
+            resultString = resultString.Trim();
             var commaIndex = resultString.IndexOf(',');
-            if (!string.IsNullOrEmpty(resultString.Trim()))
+
+            if (commaIndex != -1)
             {
-                return resultString.Substring(0, commaIndex).Substring("Maya ".Length);
+                const int versionStart = 5; // length of "Maya "
+                return resultString.Length > versionStart ? resultString.Substring(0, commaIndex).Substring(versionStart) : null;
             }
             else
             {

Assets/FbxExporters/Editor/UnitTests/FbxExportSettingsTest.cs

@@ -10,6 +10,10 @@ namespace FbxExporters.UnitTests
     public class FbxExportSettingsTest : ExporterTestBase{
         ExportSettings m_originalSettings;
 
+        //For resetting environment variables:
+        string originalVendorLocation = null;
+        string originalMayaLocation = null;
+
         // We read two private fields for the test.
         static System.Reflection.FieldInfo s_InstanceField; // static
         static System.Reflection.FieldInfo s_SavePathField; // member
@@ -356,6 +360,10 @@ public void VendorLocationInstallationTest1()
         //TearDown
         public void VendorLocations_TearDown(List<string> vendorInstallFolders)
         {
+            //Put the environment variables back to what they were originally
+            System.Environment.SetEnvironmentVariable("UNITY_FBX_3DAPP_VENDOR_LOCATIONS", originalVendorLocation);
+            System.Environment.SetEnvironmentVariable("MAYA_LOCATION", originalMayaLocation);
+
             //Clean up vendor location(s)
             foreach (var vendorLocation in vendorInstallFolders)
             {
@@ -412,6 +420,10 @@ public void SetEnvironmentVariables(string vendorLocation, string mayaLocationPa
 
         public void VendorLocations_Setup(List<string> paths)
         {
+            //Preserve our environment variables for later
+            originalVendorLocation = System.Environment.GetEnvironmentVariable("UNITY_FBX_3DAPP_VENDOR_LOCATIONS");
+            originalMayaLocation = System.Environment.GetEnvironmentVariable("MAYA_LOCATION");
+
             foreach (var pathToExe in paths)
             {
                 //make the directory