Handle empty TranslationInfo tag properly when parsing Settings.xml

src/SIL.Machine/Corpora/ParatextProjectSettingsParserBase.cs

@@ -123,12 +123,12 @@ public ParatextProjectSettings Parse()
             string translationType = "Standard";
             string parentName = null;
             string parentGuid = null;
-            if (translationInfoSetting != null)
+            string[] translationInfoSettingParts = translationInfoSetting?.Split(':');
+            if (translationInfoSettingParts?.Length == 3)
             {
-                string[] translationInfoSettingParts = translationInfoSetting.Split(':');
                 translationType = translationInfoSettingParts[0];
-                parentName = translationInfoSettingParts[1] != "" ? translationInfoSettingParts[1] : null;
-                parentGuid = translationInfoSettingParts[2] != "" ? translationInfoSettingParts[2] : null;
+                parentName = translationInfoSettingParts[1] != string.Empty ? translationInfoSettingParts[1] : null;
+                parentGuid = translationInfoSettingParts[2] != string.Empty ? translationInfoSettingParts[2] : null;
             }
 
             var settings = new ParatextProjectSettings(

tests/SIL.Machine.Tests/Corpora/MemoryParatextProjectFileHandler.cs

@@ -9,6 +9,8 @@ public class MemoryParatextProjectFileHandler(IDictionary<string, string>? files
 
     public UsfmStylesheet CreateStylesheet(string fileName)
     {
+        if (fileName is "usfm.sty" or "usfm_sb.sty")
+            return new UsfmStylesheet(fileName);
         throw new NotImplementedException();
     }
 

tests/SIL.Machine.Tests/Corpora/MemoryParatextProjectSettingsParser.cs

@@ -0,0 +1,6 @@
+namespace SIL.Machine.Corpora;
+
+public class MemoryParatextProjectSettingsParser(
+    IDictionary<string, string>? files = null,
+    ParatextProjectSettings? parentSettings = null
+) : ParatextProjectSettingsParserBase(new MemoryParatextProjectFileHandler(files), parentSettings);

tests/SIL.Machine.Tests/Corpora/ParatextProjectSettingsParserTests.cs

@@ -0,0 +1,61 @@
+using NUnit.Framework;
+
+namespace SIL.Machine.Corpora;
+
+[TestFixture]
+public class ParatextProjectSettingsParserTests
+{
+    [Test]
+    public void TranslationInfoEmptyValues()
+    {
+        ParatextProjectSettings settings = CreateSettings("<TranslationInfo></TranslationInfo>");
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(settings.TranslationType, Is.EqualTo("Standard"));
+            Assert.That(settings.ParentName, Is.Null);
+            Assert.That(settings.ParentGuid, Is.Null);
+        }
+    }
+
+    [Test]
+    public void TranslationInfoNoParentSpecified()
+    {
+        ParatextProjectSettings settings = CreateSettings("<TranslationInfo>BackTranslation::</TranslationInfo>");
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(settings.TranslationType, Is.EqualTo("BackTranslation"));
+            Assert.That(settings.ParentName, Is.Null);
+            Assert.That(settings.ParentGuid, Is.Null);
+        }
+    }
+
+    [Test]
+    public void TranslationInfoSpecified()
+    {
+        ParatextProjectSettings settings = CreateSettings(
+            "<TranslationInfo>Daughter:DEF:22222222222222222222222222222222</TranslationInfo>"
+        );
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(settings.TranslationType, Is.EqualTo("Daughter"));
+            Assert.That(settings.ParentName, Is.EqualTo("DEF"));
+            Assert.That(settings.ParentGuid, Is.EqualTo("22222222222222222222222222222222"));
+        }
+    }
+
+    private static ParatextProjectSettings CreateSettings(string additionalSettingsXml = "")
+    {
+        var files = new Dictionary<string, string>
+        {
+            ["Settings.xml"] =
+                "<ScriptureText>"
+                + "<Guid>11111111111111111111111111111111</Guid>"
+                + "<Name>ABC</Name>"
+                + "<FullName>Test Project</FullName>"
+                + additionalSettingsXml
+                + "</ScriptureText>",
+        };
+        var parser = new MemoryParatextProjectSettingsParser(files);
+        return parser.Parse();
+    }
+}