Multi-valued variants (#2386)

Modifications:
- added support for multi-valued variants
- refactored code related to variants into variant.py
- added new generic features to AutotoolsPackage that leverage multi-valued variants
- modified openmpi to use new features
- added unit tests for the new semantics

1 files changed, 31 insertions, 1 deletions

diff --git a/var/spack/repos/builtin.mock/packages/a/package.py b/var/spack/repos/builtin.mock/packages/a/package.py
index 0d75ee1256..b697f4d2a9 100644
--- a/var/spack/repos/builtin.mock/packages/a/package.py
+++ b/var/spack/repos/builtin.mock/packages/a/package.py
@@ -25,7 +25,7 @@
 from spack import *
 
 
-class A(Package):
+class A(AutotoolsPackage):
     """Simple package with no dependencies"""
 
     homepage = "http://www.example.com"
@@ -33,5 +33,35 @@ class A(Package):
 
     version('1.0', '0123456789abcdef0123456789abcdef')
 
+    variant(
+        'foo',
+        values=('bar', 'baz', 'fee'),
+        default='bar',
+        description='',
+        multi=True
+    )
+
+    variant(
+        'foobar',
+        values=('bar', 'baz', 'fee'),
+        default='bar',
+        description='',
+        multi=False
+    )
+
+    def with_or_without_fee(self, activated):
+        if not activated:
+            return '--no-fee'
+        return '--fee-all-the-time'
+
+    def autoreconf(self, spec, prefix):
+        pass
+
+    def configure(self, spec, prefix):
+        pass
+
+    def build(self, spec, prefix):
+        pass
+
     def install(self, spec, prefix):
         pass