Adjust e3.os.process.Run attributes out, err, raw_out, raw_err

Ensure that those attributes are never set to None. In case there
is no output or error just use the default empty bytes/str.

This simplify typing

eng/shared/anod#618

Author: Nikokrock

src/e3/mock/os/process.py

@@ -60,8 +60,8 @@ def __init__(
         self,
         cmd: list[str],
         status: int | None = None,
-        raw_out: bytes | None = None,
-        raw_err: bytes | None = None,
+        raw_out: bytes = b"",
+        raw_err: bytes = b"",
     ) -> None:
         """Initialize CommandResult.
 
@@ -72,8 +72,8 @@ def __init__(
         """
         self.cmd = cmd
         self.status = status if status is not None else 0
-        self.raw_out = raw_out if raw_out is not None else b""
-        self.raw_err = raw_err if raw_err is not None else b""
+        self.raw_out = raw_out
+        self.raw_err = raw_err
 
     def check(self, cmd: list[str]) -> None:
         """Check that cmd matches the expected arguments.
@@ -140,8 +140,8 @@ def __call__(self, cmds: AnyCmdLine, *args: Any, **kwargs: Any) -> Run:
         :param kwargs: unhandled keyword arguments
         """
         self.status: int | None = None
-        self.raw_out: bytes | None = b""
-        self.raw_err: bytes | None = b""
+        self.raw_out: bytes = b""
+        self.raw_err: bytes = b""
 
         cmds = to_cmd_lines(cmds)
         results: list[CommandResult] | None = self.config.get("results")

src/e3/os/process.py

@@ -366,8 +366,8 @@ def add_interpreter_command(cmd_line: CmdLine) -> CmdLine:
         self.error_file = File(error, "w")
 
         self.status: int | None = None
-        self.raw_out: bytes | None = b""
-        self.raw_err: bytes | None = b""
+        self.raw_out: bytes = b""
+        self.raw_err: bytes = b""
         self.cmds = []
 
         if env is not None:
@@ -488,25 +488,23 @@ def add_interpreter_command(cmd_line: CmdLine) -> CmdLine:
             self.wait()
 
     @property
-    def out(self) -> str | None:
+    def out(self) -> str:
         """Process output as string.
 
         Attempt is done to decode as utf-8 the output. If the output is not in
         utf-8 a string representation will be returned
         (see e3.text.bytes_as_str).
         """
-        return bytes_as_str(self.raw_out) if self.raw_out is not None else None
+        return bytes_as_str(self.raw_out)
 
     @property
-    def err(self) -> str | None:
+    def err(self) -> str:
         """Process error as string.
 
         Attempt is done to decode as utf-8 the output. If the output is not in
         utf-8 a string representation will be returned
         (see e3.text.bytes_as_str).
         """
-        if self.raw_err is None:
-            return None
         return bytes_as_str(self.raw_err)
 
     def command_line_image(self) -> str:
@@ -569,7 +567,10 @@ def wait(self) -> int:
             if isinstance(tmp_input, str):
                 tmp_input = tmp_input.encode("utf-8")
 
-            (self.raw_out, self.raw_err) = self.internal.communicate(tmp_input)
+            (raw_out, raw_err) = self.internal.communicate(tmp_input)
+            self.raw_out = raw_out if raw_out is not None else b""
+            self.raw_err = raw_err if raw_err is not None else b""
+
             self.status = self.internal.returncode
 
         self.close_files()

tests/tests_e3/os/process/main_test.py

@@ -17,7 +17,7 @@
 
 import pytest
 
-from subprocess import STDOUT
+from subprocess import STDOUT, PIPE
 
 try:
     import psutil
@@ -561,5 +561,26 @@ def test_shell_override():
 
 
 def test_error_to_stdout():
-    p = e3.os.process.Run(["echo", "1"], error=STDOUT)
-    assert p.err is None
+    """Check that redirection of stderr to stdout works."""
+    python_cmd = ";".join(
+        [
+            "import sys; sys.stderr.write('hello_from_stderr')",
+            "sys.stderr.flush()",
+            "sys.stdout.write('hello_from_stdout')",
+        ]
+    )
+
+    # Test merge of STDERR in STDOUT
+    p = e3.os.process.Run([sys.executable, "-c", python_cmd], error=STDOUT)
+    assert p.out == "hello_from_stderrhello_from_stdout"
+    assert p.err == ""
+
+    # This is in fact the default behavior
+    p = e3.os.process.Run([sys.executable, "-c", python_cmd])
+    assert p.out == "hello_from_stderrhello_from_stdout"
+    assert p.err == ""
+
+    # Check when the STDERR and STDOUT are sepearate pipes.
+    p = e3.os.process.Run([sys.executable, "-c", python_cmd], error=PIPE)
+    assert p.out == "hello_from_stdout"
+    assert p.err == "hello_from_stderr"