morph3: Add a get_commands method to Morphology

morph2.Morphology has a `get_commands` method which is used to return
the [configure|build|install]-commands of the chunk, either by getting
them from the chunk morphology or from the build system of the chunk.

This commit implements a similar method in morph3.Morphology and adds
tests for it, so that when we remove morph2 the API changes to
morphologies are minimal.

2 files changed, 46 insertions, 2 deletions

diff --git a/morphlib/morph3.py b/morphlib/morph3.py
index 477cac1a..a91ff390 100644
--- a/morphlib/morph3.py
+++ b/morphlib/morph3.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2013  Codethink Limited
+# Copyright (C) 2013-2014  Codethink Limited
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -18,6 +18,8 @@
 
 import UserDict
 
+import morphlib
+
 
 class Morphology(UserDict.IterableUserDict):
 
@@ -43,3 +45,11 @@ class Morphology(UserDict.IterableUserDict):
         self.filename = None
         self.dirty = None
 
+    def get_commands(self, which):
+        '''Return the commands to run from a morphology or the build system'''
+        if self.get(which, None) is None:
+            attr = '_'.join(which.split('-'))
+            bs = morphlib.buildsystem.lookup_build_system(self['build-system'])
+            return getattr(bs, attr)
+        else:
+            return self[which]
diff --git a/morphlib/morph3_tests.py b/morphlib/morph3_tests.py
index e150bf33..51b70597 100644
--- a/morphlib/morph3_tests.py
+++ b/morphlib/morph3_tests.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2013  Codethink Limited
+# Copyright (C) 2013-2014  Codethink Limited
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -46,3 +46,37 @@ class MorphologyTests(unittest.TestCase):
         self.morph.dirty = True
         self.assertEqual(self.morph.dirty, True)
 
+    def test_uses_morphology_commands_when_given(self):
+        m = morphlib.morph3.Morphology(
+            {
+                'name': 'foo',
+                'kind': 'chunk',
+                'build-system': 'dummy',
+                'build-commands': ['build-it']
+            }
+        )
+        cmds = m.get_commands('build-commands')
+        self.assertEqual(cmds, ['build-it'])
+
+    def test_uses_build_system_commands_when_morphology_doesnt(self):
+        m = morphlib.morph3.Morphology(
+            {
+                'name': 'foo',
+                'kind': 'chunk',
+                'build-system': 'dummy',
+            }
+        )
+        cmds = m.get_commands('build-commands')
+        self.assertEqual(cmds, ['echo dummy build'])
+
+    def test_uses_morphology_commands_when_morphology_has_empty_list(self):
+        m = morphlib.morph3.Morphology(
+            {
+                'name': 'foo',
+                'kind': 'chunk',
+                'build-system': 'dummy',
+                'build-commands': []
+            }
+        )
+        cmds = m.get_commands('build-commands')
+        self.assertEqual(cmds, [])