self install: in this context the project is not a package so we shou…

…ld set package-mode

src/poetry/console/commands/self/self_command.py

@@ -73,6 +73,7 @@ def generate_system_pyproject(self) -> None:
         package.python_versions = ".".join(str(v) for v in self.env.version_info[:3])
 
         content = Factory.create_pyproject_from_package(package=package)
+        content["tool"]["poetry"]["package-mode"] = False
 
         for key in preserved:
             content["tool"]["poetry"][key] = preserved[key]  # type: ignore[index]

tests/console/commands/self/test_install.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import pytest
+
+
+if TYPE_CHECKING:
+    from cleo.testers.command_tester import CommandTester
+
+    from tests.types import CommandTesterFactory
+
+
+@pytest.fixture
+def tester(command_tester_factory: CommandTesterFactory) -> CommandTester:
+    return command_tester_factory("self install")
+
+
+def test_self_install(
+    tester: CommandTester,
+) -> None:
+    tester.execute()
+
+    expected_output = """\
+Updating dependencies
+Resolving dependencies...
+
+Writing lock file
+"""
+
+    assert tester.io.fetch_output() == expected_output
+    assert tester.io.fetch_error() == ""