added more tests

Core/Base32.cs

@@ -24,6 +24,8 @@ public static class Base32
     [Pure]
     public static int Encode(ReadOnlySpan<byte> input, Span<char> output)
     {
+        if (input.IsEmpty) return 0;
+
         int i = 0;
         ReadOnlySpan<char> alphabet = Alphabet;
         for (int offset = 0; offset < input.Length;)

Core/Base64Url.cs

@@ -95,6 +95,8 @@ public static class Base64Url
 
     [Pure] public static int Encode(ReadOnlySpan<byte> input, Span<char> output)
     {
+        if (input.IsEmpty) return 0;
+
         var charlen = 8 * ((input.Length + 5) / 6);
         Span<char> chars = stackalloc char[charlen];
         Convert.TryToBase64Chars(input, chars, out int charsWritten);

Core/Extensions/SystemIOStreamExtensions.cs

@@ -8,7 +8,7 @@ public static class SystemIOStreamExtensions
         => stream.Populate(buffer.AsSpan());
     public static void Populate(this Stream stream, Span<byte> buffer)
     {
-        do
+        while (buffer.Length > 0)
         {
             var readed = stream.Read(buffer);
 
@@ -19,7 +19,6 @@ public static class SystemIOStreamExtensions
 
             buffer = buffer[readed..];
         }
-        while (buffer.Length > 0);
     }
 
     public static async ValueTask PopulateAsync(this Stream stream, byte[] buffer, CancellationToken cancellationToken = default)
@@ -28,7 +27,7 @@ public static class SystemIOStreamExtensions
         => await stream.PopulateAsync(buffer.AsMemory(offset, length), cancellationToken);
     public static async ValueTask PopulateAsync(this Stream stream, Memory<byte> buffer, CancellationToken cancellationToken = default)
     {
-        do
+        while (buffer.Length > 0)
         {
             cancellationToken.ThrowIfCancellationRequested();
 
@@ -41,6 +40,5 @@ public static class SystemIOStreamExtensions
 
             buffer = buffer[readed..];
         }
-        while (buffer.Length > 0);
     }
 }