true color and 256 terminal formatters added and use PYTEST_THEME env variable for style

AUTHORS

@@ -308,6 +308,7 @@ Omar Kohl
 Omer Hadari
 Ondřej Súkup
 Oscar Benjamin
+Pandula Gajadeera
 Parth Patel
 Patrick Hayes
 Patrick Lannigan

changelog/11666.imporvement.rst

@@ -0,0 +1,5 @@
+Improved the terminal writer to be able to use Terminal256Formatter and TerminalTrueColorFormatter.
+
+These are newer versions of TerminalFormmater from the pygments library that is currently in use.
+
+These style of these formatters are set by the users through the environmental variable PYTEST_THEME.

src/_pytest/_io/terminalwriter.py

@@ -194,9 +194,9 @@ class TerminalWriter:
         for indent, new_line in zip(indents, new_lines):
             self.line(indent + new_line)
 
-    def _highlight(
+def _highlight(
     self, source: str, lexer: Literal["diff", "python"] = "python"
-    ) -> str:
+) -> str:
     """Highlight the given source if we have markup support."""
     from _pytest.config.exceptions import UsageError
 
@@ -212,8 +212,20 @@ class TerminalWriter:
             from pygments.lexers.diff import DiffLexer as Lexer
         else:
             assert_never(lexer)
+
         from pygments import highlight
         import pygments.util
+
+        if os.getenv("COLORTERM", "") in ("truecolor", "24bit"):
+            from pygments.formatters.terminal256 import TerminalTrueColorFormatter
+            terminal_formatter = TerminalTrueColorFormatter(style=os.getenv("PYTEST_THEME", "default"))
+        elif "256" in os.getenv("TERM", ""):
+            from pygments.formatters.terminal256 import Terminal256Formatter
+            terminal_formatter = Terminal256Formatter(style=os.getenv("PYTEST_THEME", "default"))
+        else:
+            terminal_formatter = TerminalFormatter(bg=os.getenv("PYTEST_THEME_MODE", "dark"),
+                                                    style=os.getenv("PYTEST_THEME", "default"))
+
     except ImportError:
         return source
     else:
@@ -221,10 +233,7 @@ class TerminalWriter:
             highlighted: str = highlight(
                 source,
                 Lexer(),
-                    TerminalFormatter(
-                        bg=os.getenv("PYTEST_THEME_MODE", "dark"),
-                        style=os.getenv("PYTEST_THEME"),
-                    ),
+                terminal_formatter,
             )
             # pygments terminal formatter may add a newline when there wasn't one.
             # We don't want this, remove.