Add tests for RT#107204

Also adjust comments for autogenned RTs that can be merged

S32-str/encode.t

@@ -1,6 +1,6 @@
 use v6;
 use Test;
-plan 28;
+plan 32;
 
 
 # L<S32::Containers/Buf>
@@ -16,6 +16,16 @@ is '€‚ƒ„…†‡ˆ‰Š‹ŒŽ'.encode('windows-1252').values, (0x80,0x8
 #?rakudo.jvm todo 'builtin JVM cp1252 code folds these RT #124686'
 is ''.encode('windows-1252').values, (0x81,0x8d,0x8f), 'cp1252 encode tolerates unassigned C1 characters';
 
+# RT#107204
+#?rakudo.jvm todo 'JVM builtin code folds these RT #124686'
+throws-like '"aouÄÖÜ".encode("latin1").decode("utf8")', X::AdHoc, message => rx:s:i/line 1 col\w* 4/;
+#?rakudo.jvm todo 'JVM builtin code folds these RT #124686'
+throws-like '"ssß".encode("latin1").decode("utf8")', X::AdHoc, message => rx:s:i/term/;
+#?rakudo todo 'RT#107204 should say line and column or mention term(ination)'
+throws-like '"aoaou".encode("latin1").decode("utf16")', X::AdHoc, message => rx:s:i/line 1 col\w* 2|term/;
+#?rakudo todo 'RT#107204 should say line and column'
+throws-like '"aouÄÖÜ".encode("latin1").decode("utf16")', X::AdHoc, message => rx:s:i/line 1 col\w* 2/;
+
 is 'abc'.encode()[0], 97, 'can index one element in a Buf';
 is-deeply 'abc'.encode()[1, 2], (98, 99), 'can slice-index a Buf';
 
@@ -32,7 +42,7 @@ ok Buf.new(195, 182).decode ~~ Str, '.decode returns a Str';
 is Buf.new(195, 182).decode, 'ö', 'decoding a Buf with UTF-8';
 is Buf.new(246).decode('ISO-8859-1'), 'ö', 'decoding a Buf with Latin-1';
 is Buf.new(0x80,0x82..0x8c,0x8e).decode('windows-1252'),'€‚ƒ„…†‡ˆ‰Š‹ŒŽ', 'cp1252 decodes most C1 substitutes';
-#?rakudo.jvm todo 'builtin JVM cp1252 code folds these RT #124688'
+#?rakudo.jvm todo 'builtin JVM cp1252 code folds these RT #124686'
 is Buf.new(0x81,0x8d,0x8f).decode('windows-1252'), '', 'cp1252 decode tolerates unassigned C1 characters';
 
 ok Buf ~~ Stringy, 'Buf does Stringy';