concretizer: allow a bool to be passed as argument for tests dependencies (#20082)

refers #20079

Added docstrings to 'concretize' and 'concretized' to
document the format for tests.

Added tests for the activation of test dependencies.

lib/spack/spack/solver/asp.py

@@ -916,8 +916,13 @@ def package_dependencies_rules(self, pkg, tests):
                 named_cond.name = named_cond.name or pkg.name
 
                 for t in sorted(dep.type):
-                    # Skip test dependencies if they're not requested
-                    if t == 'test' and (not tests or pkg.name not in tests):
+                    # Skip test dependencies if they're not requested at all
+                    if t == 'test' and not tests:
+                        continue
+
+                    # ... or if they are requested only for certain packages
+                    if t == 'test' and (not isinstance(tests, bool)
+                                        and pkg.name not in tests):
                         continue
 
                     if cond == spack.spec.Spec():

lib/spack/spack/spec.py

@@ -2463,8 +2463,14 @@ def _new_concretize(self, tests=False):
         self._dup(concretized)
         self._mark_concrete()
 
-    #: choose your concretizer here.
     def concretize(self, tests=False):
+        """Concretize the current spec.
+
+        Args:
+            tests (bool or list): if False disregard 'test' dependencies,
+                if a list of names activate them for the packages in the list,
+                if True activate 'test' dependencies for all packages.
+        """
         if spack.config.get('config:concretizer') == "clingo":
             self._new_concretize(tests)
         else:
@@ -2482,12 +2488,19 @@ def _mark_concrete(self, value=True):
             s._normal = value
             s._concrete = value
 
-    def concretized(self):
-        """This is a non-destructive version of concretize().  First clones,
-           then returns a concrete version of this package without modifying
-           this package. """
+    def concretized(self, tests=False):
+        """This is a non-destructive version of concretize().
+
+        First clones, then returns a concrete version of this package
+        without modifying this package.
+
+        Args:
+            tests (bool or list): if False disregard 'test' dependencies,
+                if a list of names activate them for the packages in the list,
+                if True activate 'test' dependencies for all packages.
+        """
         clone = self.copy(caches=False)
-        clone.concretize()
+        clone.concretize(tests=tests)
         return clone
 
     def flat_dependencies(self, **kwargs):

lib/spack/spack/test/concretize.py

@@ -895,3 +895,31 @@ def test_conditional_provides_or_depends_on(self):
         assert 'v1-provider' in s
         assert s['v1'].name == 'v1-provider'
         assert s['v2'].name == 'conditional-provider'
+
+    @pytest.mark.regression('20079')
+    @pytest.mark.parametrize('spec_str,tests_arg,with_dep,without_dep', [
+        # Check that True is treated correctly and attaches test deps
+        # to all nodes in the DAG
+        ('a', True, ['a'], []),
+        ('a foobar=bar', True, ['a', 'b'], []),
+        # Check that a list of names activates the dependency only for
+        # packages in that list
+        ('a foobar=bar', ['a'], ['a'], ['b']),
+        ('a foobar=bar', ['b'], ['b'], ['a']),
+        # Check that False disregard test dependencies
+        ('a foobar=bar', False, [], ['a', 'b']),
+    ])
+    def test_activating_test_dependencies(
+            self, spec_str, tests_arg, with_dep, without_dep
+    ):
+        s = Spec(spec_str).concretized(tests=tests_arg)
+
+        for pkg_name in with_dep:
+            msg = "Cannot find test dependency in package '{0}'"
+            node = s[pkg_name]
+            assert node.dependencies(deptype='test'), msg.format(pkg_name)
+
+        for pkg_name in without_dep:
+            msg = "Test dependency in package '{0}' is unexpected"
+            node = s[pkg_name]
+            assert not node.dependencies(deptype='test'), msg.format(pkg_name)