tests: make the dependency patching test more complete

- dependency patching test didn't attempt to apply patches; just to see
  whether they were on the spec.

- it applies the patch now and verifies that that patch was applied.

lib/spack/spack/test/conftest.py

@@ -388,6 +388,7 @@ def install_mockery(tmpdir, config, mock_packages):
     with spack.config.override('config:checksum', False):
         yield
 
+    tmpdir.join('opt').remove()
     spack.store.store = real_store
 
 

lib/spack/spack/test/patch.py

@@ -31,6 +31,7 @@
 
 import spack.paths
 import spack.util.compression
+from spack.util.executable import Executable
 from spack.stage import Stage
 from spack.spec import Spec
 
@@ -108,16 +109,32 @@ def test_patch_in_spec(mock_packages, config):
             spec.variants['patches'].value)
 
 
-def test_patched_dependency(mock_packages, config):
+def test_patched_dependency(
+        mock_packages, config, install_mockery, mock_fetch):
     """Test whether patched dependencies work."""
     spec = Spec('patch-a-dependency')
     spec.concretize()
     assert 'patches' in list(spec['libelf'].variants.keys())
 
-    # foo
+    # make sure the patch makes it into the dependency spec
-    assert (('b5bb9d8014a0f9b1d61e21e796d78dccdf1352f23cd32812f4850b878ae4944c',) ==
+    assert (('c45c1564f70def3fc1a6e22139f62cb21cd190cc3a7dbe6f4120fa59ce33dcb8',) ==
             spec['libelf'].variants['patches'].value)
 
+    # make sure the patch in the dependent's directory is applied to the
+    # dependency
+    libelf = spec['libelf']
+    pkg = libelf.package
+    pkg.do_patch()
+    with pkg.stage:
+        with working_dir(pkg.stage.source_path):
+            # output a Makefile with 'echo Patched!' as the default target
+            configure = Executable('./configure')
+            configure()
+
+            # Make sure the Makefile contains the patched text
+            with open('Makefile') as mf:
+                assert 'Patched!' in mf.read()
+
 
 def test_multiple_patched_dependencies(mock_packages, config):
     """Test whether multiple patched dependencies work."""

var/spack/repos/builtin.mock/packages/patch-a-dependency/foo.patch

@@ -1 +0,0 @@
-foo

var/spack/repos/builtin.mock/packages/patch-a-dependency/libelf.patch

@@ -0,0 +1,11 @@
+--- patch-a-dependency/configure	2018-08-13 23:13:51.000000000 -0700
++++ patch-a-dependency/configure.patched	2018-08-13 23:14:15.000000000 -0700
+@@ -2,7 +2,7 @@
+ prefix=$(echo $1 | sed 's/--prefix=//')
+ cat > Makefile <<EOF
+ all:
+-	echo Building...
++	echo Patched!
+ 
+ install:
+ 	mkdir -p $prefix

var/spack/repos/builtin.mock/packages/patch-a-dependency/package.py

@@ -33,7 +33,7 @@ class PatchADependency(Package):
 
     version('1.0', '0123456789abcdef0123456789abcdef')
 
-    depends_on('libelf', patches=patch('foo.patch'))
+    depends_on('libelf', patches=patch('libelf.patch'))
 
     def install(self, spec, prefix):
         pass