allow test_requires(..., force=True)

conans/model/requires.py

@@ -408,8 +408,8 @@ class TestRequirements:
     def __init__(self, requires):
         self._requires = requires
 
-    def __call__(self, ref, run=None, options=None):
-        self._requires.test_require(ref, run=run, options=options)
+    def __call__(self, ref, run=None, options=None, force=None):
+        self._requires.test_require(ref, run=run, options=options, force=force)
 
 
 class Requirements:
@@ -510,7 +510,7 @@ def override(self, ref):
             req.override = True
             self._requires[req] = req
 
-    def test_require(self, ref, run=None, options=None):
+    def test_require(self, ref, run=None, options=None, force=None):
         """
              Represent a testing framework like gtest
 
@@ -526,7 +526,7 @@ def test_require(self, ref, run=None, options=None):
         # libs = True => We need to link with it
         # headers = True => We need to include it
         req = Requirement(ref, headers=True, libs=True, build=False, run=run, visible=False,
-                          test=True, package_id_mode=None, options=options)
+                          test=True, package_id_mode=None, options=options, force=force)
         if self._requires.get(req):
             raise ConanException("Duplicated requirement: {}".format(ref))
         self._requires[req] = req

conans/test/integration/graph/test_test_requires.py

@@ -87,6 +87,27 @@ def requirements(self):
                                  "engine/1.0": "Cache"})
         c.assert_listed_require({"gtest/1.0": "Cache"}, test=True)
 
+    def test_test_requires_conflict_force(self):
+        c = TestClient()
+        game = textwrap.dedent("""
+           from conan import ConanFile
+           class Pkg(ConanFile):
+               def requirements(self):
+                   self.test_requires("gtest/1.0", force=True)
+                   self.test_requires("rapidcheck/1.0")
+           """)
+        c.save({"gtest/conanfile.py": GenConanfile("gtest"),
+                "rapidcheck/conanfile.py":
+                    GenConanfile("rapidcheck", "1.0").with_requires("gtest/1.1"),
+                "game/conanfile.py": game
+                })
+        c.run("create gtest --version=1.0")
+        c.run("create gtest --version=1.1")
+        c.run("create rapidcheck")
+        c.run("install game")
+        c.assert_listed_require({"gtest/1.0": "Cache"}, test=True)
+        c.assert_overrides({"gtest/1.1": ["gtest/1.0#08dd14dd79315dd95c94b85d13bd1388"]})
+
 
 def test_require_options():
     c = TestClient()