Add test instructions

DiscordChatExporter.Cli.Tests/Infra/Secrets.cs

@@ -24,12 +24,19 @@ namespace DiscordChatExporter.Cli.Tests.Infra
 
         private static readonly Lazy<bool> IsDiscordTokenBotLazy = new(() =>
         {
-            // Default to true
             var fromEnvironment = Environment.GetEnvironmentVariable("DISCORD_TOKEN_BOT");
-            if (string.IsNullOrWhiteSpace(fromEnvironment))
+            if (!string.IsNullOrWhiteSpace(fromEnvironment))
+                return string.Equals(fromEnvironment, "true", StringComparison.OrdinalIgnoreCase);
+
+            var secretFilePath = Path.Combine(
+                Path.GetDirectoryName(typeof(Secrets).Assembly.Location) ?? Directory.GetCurrentDirectory(),
+                "DiscordTokenBot.secret"
+            );
+
+            if (File.Exists(secretFilePath))
                 return true;
 
-            return string.Equals(fromEnvironment, "true", StringComparison.OrdinalIgnoreCase);
+            return false;
         });
 
         public static string DiscordToken => DiscordTokenLazy.Value;

DiscordChatExporter.Cli.Tests/Readme.md

@@ -0,0 +1,17 @@
+# DiscordChatExporter Tests
+
+This test suite runs against a real Discord server, specifically created to exercise different behaviors required by the test scenarios.
+In order to run these tests locally, you need to join the test server and configure your authentication token.
+
+1. Join the server: https://discord.gg/eRV8Vap5bm
+2. Locate your Discord authentication token
+3. Specify your token using a file or an environment variable:
+  - **Using a file**: put your token in a new `DiscordToken.secret` file created in this directory
+  - **Using an environment variable**: set `DISCORD_TOKEN` variable to your token
+4. Run the tests: `dotnet test`
+
+> 🟣 If you're submitting a pull request, you don't _have_ to run the tests locally -- they are executed automatically by CI.
+Running them locally can still sometimes be useful for debugging purposes though.
+ 
+> 🟣 If you want to have a new test case or a scenario added, please let me know in your pull request.
+Currently, it's not possible to add them by yourself.