terminal: add a TerminalReporter.write_raw method

The `write` method does some processing on the input, namely markup and
adding to the current line. `write_raw` skips these parts. It is useful
for emitting invisible escape sequences.

Author: bluetech

src/_pytest/_io/terminalwriter.py

@@ -161,20 +161,23 @@ def write(self, msg: str, *, flush: bool = False, **markup: bool) -> None:
 
             msg = self.markup(msg, **markup)
 
-            try:
-                self._file.write(msg)
-            except UnicodeEncodeError:
-                # Some environments don't support printing general Unicode
-                # strings, due to misconfiguration or otherwise; in that case,
-                # print the string escaped to ASCII.
-                # When the Unicode situation improves we should consider
-                # letting the error propagate instead of masking it (see #7475
-                # for one brief attempt).
-                msg = msg.encode("unicode-escape").decode("ascii")
-                self._file.write(msg)
-
-            if flush:
-                self.flush()
+            self.write_raw(msg, flush=flush)
+
+    def write_raw(self, msg: str, *, flush: bool = False) -> None:
+        try:
+            self._file.write(msg)
+        except UnicodeEncodeError:
+            # Some environments don't support printing general Unicode
+            # strings, due to misconfiguration or otherwise; in that case,
+            # print the string escaped to ASCII.
+            # When the Unicode situation improves we should consider
+            # letting the error propagate instead of masking it (see #7475
+            # for one brief attempt).
+            msg = msg.encode("unicode-escape").decode("ascii")
+            self._file.write(msg)
+
+        if flush:
+            self.flush()
 
     def line(self, s: str = "", **markup: bool) -> None:
         self.write(s, **markup)

src/_pytest/terminal.py

@@ -508,6 +508,9 @@ def wrap_write(
     def write(self, content: str, *, flush: bool = False, **markup: bool) -> None:
         self._tw.write(content, flush=flush, **markup)
 
+    def write_raw(self, content: str, *, flush: bool = False) -> None:
+        self._tw.write_raw(content, flush=flush)
+
     def flush(self) -> None:
         self._tw.flush()