Add new layout() test for projects sharing common code in parent folders

conans/test/functional/layout/test_in_subfolder.py

@@ -54,3 +54,55 @@ def build(self):
     c.run("build conan")
     assert "conanfile.py (pkg/0.1): MYCMAKE-BUILD: mycmake!" in c.out
     assert c.load("build/mylib.a") == "mylib"
+
+
+def test_exports_sources_common_code():
+    """ very similar to the above, but intended for a multi-package project sharing some
+    common code
+    """
+    c = TestClient()
+    conanfile = textwrap.dedent("""
+        import os
+        from conan import ConanFile
+        from conan.tools.files import load, copy, save
+        class Pkg(ConanFile):
+            name = "pkg"
+            version = "0.1"
+
+            def layout(self):
+                self.folders.root = ".."
+                self.folders.source = "pkg"
+                self.folders.build = "build"
+
+            def export_sources(self):
+                source_folder = os.path.join(self.recipe_folder, "..")
+                copy(self, "*.txt", source_folder, self.export_sources_folder)
+                copy(self, "*.cmake", source_folder, self.export_sources_folder)
+
+            def source(self):
+                cmake = load(self, "CMakeLists.txt")
+                self.output.info("MYCMAKE-SRC: {}".format(cmake))
+
+            def build(self):
+                path = os.path.join(self.source_folder, "CMakeLists.txt")
+                cmake = load(self, path)
+                self.output.info("MYCMAKE-BUILD: {}".format(cmake))
+
+                path = os.path.join(self.export_sources_folder, "common", "myutils.cmake")
+                cmake = load(self, path)
+                self.output.info("MYUTILS-BUILD: {}".format(cmake))
+            """)
+    c.save({"pkg/conanfile.py": conanfile,
+            "pkg/CMakeLists.txt": "mycmake!",
+            "common/myutils.cmake": "myutils!"})
+    c.run("create pkg")
+    assert "pkg/0.1: MYCMAKE-SRC: mycmake!" in c.out
+    assert "pkg/0.1: MYCMAKE-BUILD: mycmake!" in c.out
+    assert "pkg/0.1: MYUTILS-BUILD: myutils!" in c.out
+
+    # Local flow
+    c.run("install pkg")
+    # SOURCE NOT CALLED! It doesnt make sense (will fail due to local exports)
+    c.run("build pkg")
+    assert "conanfile.py (pkg/0.1): MYCMAKE-BUILD: mycmake!" in c.out
+    assert "conanfile.py (pkg/0.1): MYUTILS-BUILD: myutils!" in c.out