Extract method from `Database.InitializeWork`, clean up, and add test

src/BizHawk.Emulation.Common/Database/Database.cs

@@ -94,6 +94,54 @@ namespace BizHawk.Emulation.Common
 
 		private static bool initialized = false;
 
+		public static CompactGameInfo ParseCGIRecord(string line)
+		{
+			const char FIELD_SEPARATOR = '\t';
+			var items = line.Split(FIELD_SEPARATOR);
+			var field = 0;
+			var hashDigest = FormatHash(items[field++]);
+			var dumpStatus = items[field++].Trim() switch
+			{
+				"B" => RomStatus.BadDump, // see /Assets/gamedb/gamedb.txt
+				"V" => RomStatus.BadDump, // see /Assets/gamedb/gamedb.txt
+				"T" => RomStatus.TranslatedRom,
+				"O" => RomStatus.Overdump,
+				"I" => RomStatus.Bios,
+				"D" => RomStatus.Homebrew,
+				"H" => RomStatus.Hack,
+				"U" => RomStatus.Unknown,
+				_ => RomStatus.GoodDump
+			};
+			var knownName = items[field++];
+			var sysID = items[field++];
+			string/*?*/ metadata = null;
+			string region = string.Empty;
+			string forcedCore = string.Empty;
+			if (field < items.Length)
+			{
+				_ = items[field++]; // rarely populated; possibly genre or just a remark
+				if (field < items.Length)
+				{
+					metadata = items[field++];
+					if (field < items.Length)
+					{
+						region = items[field++];
+						if (field < items.Length) forcedCore = items[field++];
+					}
+				}
+			}
+			return new()
+			{
+				Hash = hashDigest,
+				Status = dumpStatus,
+				Name = knownName,
+				System = sysID,
+				MetaData = metadata,
+				Region = region,
+				ForcedCore = forcedCore,
+			};
+		}
+
 		private static void InitializeWork(string path, bool inUser, bool silent)
 		{
 			if (!inUser) _expected.Remove(Path.GetFileName(path));
@@ -115,31 +163,7 @@ namespace BizHawk.Emulation.Common
 					{
 						continue;
 					}
-
+					var game = ParseCGIRecord(line);
-					var items = line.Split('\t');
-
-					var game = new CompactGameInfo
-					{
-						Hash = FormatHash(items[0]),
-						Status = items[1].Trim()
-							switch
-						{
-							"B" => RomStatus.BadDump, // see /Assets/gamedb/gamedb.txt
-							"V" => RomStatus.BadDump, // see /Assets/gamedb/gamedb.txt
-							"T" => RomStatus.TranslatedRom,
-							"O" => RomStatus.Overdump,
-							"I" => RomStatus.Bios,
-							"D" => RomStatus.Homebrew,
-							"H" => RomStatus.Hack,
-							"U" => RomStatus.Unknown,
-							_ => RomStatus.GoodDump
-						},
-						Name = items[2],
-						System = items[3],
-						MetaData = items.Length >= 6 ? items[5] : null,
-						Region = items.Length >= 7 ? items[6] : "",
-						ForcedCore = items.Length >= 8 ? items[7].ToLowerInvariant() : ""
-					};
 					if (game.Hash is SHA1Checksum.EmptyFile or MD5Checksum.EmptyFile)
 					{
 						Console.WriteLine($"WARNING: gamedb {path} contains entry for empty rom as \"{game.Name}\"!");

src/BizHawk.Tests/Emulation.Common/Database/GameDBTSVParserTests.cs

@@ -0,0 +1,47 @@
+using BizHawk.Emulation.Common;
+
+namespace BizHawk.Tests.Emulation.Common
+{
+	[TestClass]
+	public sealed class GameDBTSVParserTests
+	{
+		[DataRow(
+			"sha1:f4885610503bff2c4ca816f4f28d1fe517b92f35\t\t2 Pak Special Yellow - Star Warrior,Frogger (1990) (HES) (PAL) [!]\tA26\t\tm=F6;PAL=true",
+			"F4885610503BFF2C4CA816F4F28D1FE517B92F35",
+			RomStatus.GoodDump,
+			"2 Pak Special Yellow - Star Warrior,Frogger (1990) (HES) (PAL) [!]",
+			"A26",
+			"m=F6;PAL=true",
+			""/*empty string*/,
+			""/*empty string*/)]
+		[DataRow(
+			"3064E664D34859649B67559F0ED0C2FFD6948031\tB\tActRaiser 2 (U) [b1]\tSNES",
+			"3064E664D34859649B67559F0ED0C2FFD6948031",
+			RomStatus.BadDump,
+			"ActRaiser 2 (U) [b1]",
+			"SNES",
+			null,
+			""/*empty string*/,
+			""/*empty string*/)]
+		[TestMethod]
+		public void Check(
+			string line,
+			string hashDigest,
+			RomStatus dumpStatus,
+			string knownName,
+			string sysID,
+			string? metadata,
+			string region,
+			string forcedCore)
+		{
+			var gi = Database.ParseCGIRecord(line);
+			Assert.AreEqual(expected: hashDigest, actual: gi.Hash, message: nameof(CompactGameInfo.Hash));
+			Assert.AreEqual(expected: dumpStatus, actual: gi.Status, message: nameof(CompactGameInfo.Status));
+			Assert.AreEqual(expected: knownName, actual: gi.Name, message: nameof(CompactGameInfo.Name));
+			Assert.AreEqual(expected: sysID, actual: gi.System, message: nameof(CompactGameInfo.System));
+			Assert.AreEqual(expected: metadata, actual: gi.MetaData, message: nameof(CompactGameInfo.MetaData));
+			Assert.AreEqual(expected: region, actual: gi.Region, message: nameof(CompactGameInfo.Region));
+			Assert.AreEqual(expected: forcedCore, actual: gi.ForcedCore, message: nameof(CompactGameInfo.ForcedCore));
+		}
+	}
+}