add environment-awareness to buildcache create (#16580)

* add buildcache create test

* add functionality and test to create buildcache from environment

* use env.concretized_user_specs rather than env.roots to get concretized specs, as suggested in review from becker33

lib/spack/spack/cmd/buildcache.py

@@ -338,10 +338,14 @@ def _createtarball(env, spec_yaml, packages, add_spec, add_deps,
     elif packages:
         packages = packages
 
+    elif env:
+        packages = env.concretized_user_specs
+
     else:
         tty.die("build cache file creation requires at least one" +
-                " installed package argument or else path to a" +
+                " installed package spec, an activate environment," +
-                " yaml file containing a spec to install")
+                " or else a path to a yaml file containing a spec" +
+                " to install")
     pkgs = set(packages)
     specs = set()
 

lib/spack/spack/test/cmd/buildcache.py

@@ -5,14 +5,19 @@
 
 import errno
 import platform
+import os
 
 import pytest
 
 import spack.main
 import spack.binary_distribution
+import spack.environment as ev
+from spack.spec import Spec
 
 buildcache = spack.main.SpackCommand('buildcache')
 install = spack.main.SpackCommand('install')
+env = spack.main.SpackCommand('env')
+add = spack.main.SpackCommand('add')
 
 
 @pytest.fixture()
@@ -45,6 +50,52 @@ def test_buildcache_list_duplicates(mock_get_specs, capsys):
     assert output.count('mpileaks') == 3
 
 
+def tests_buildcache_create(
+        install_mockery, mock_fetch, monkeypatch, tmpdir):
+    """"Ensure that buildcache create creates output files"""
+    pkg = 'trivial-install-test-package'
+    install(pkg)
+
+    buildcache('create', '-d', str(tmpdir), '--unsigned', pkg)
+
+    spec = Spec(pkg).concretized()
+    tarball_path = spack.binary_distribution.tarball_path_name(spec, '.spack')
+    tarball = spack.binary_distribution.tarball_name(spec, '.spec.yaml')
+    assert os.path.exists(
+        os.path.join(str(tmpdir), 'build_cache', tarball_path))
+    assert os.path.exists(
+        os.path.join(str(tmpdir), 'build_cache', tarball))
+
+
+def tests_buildcache_create_env(
+        install_mockery, mock_fetch, monkeypatch,
+        tmpdir, mutable_mock_env_path):
+    """"Ensure that buildcache create creates output files from env"""
+    pkg = 'trivial-install-test-package'
+
+    env('create', 'test')
+    with ev.read('test'):
+        add(pkg)
+        install()
+
+        buildcache('create', '-d', str(tmpdir), '--unsigned')
+
+    spec = Spec(pkg).concretized()
+    tarball_path = spack.binary_distribution.tarball_path_name(spec, '.spack')
+    tarball = spack.binary_distribution.tarball_name(spec, '.spec.yaml')
+    assert os.path.exists(
+        os.path.join(str(tmpdir), 'build_cache', tarball_path))
+    assert os.path.exists(
+        os.path.join(str(tmpdir), 'build_cache', tarball))
+
+
+def test_buildcache_create_fails_on_noargs(tmpdir):
+    """Ensure that buildcache create fails when given no args or
+    environment."""
+    with pytest.raises(spack.main.SpackCommandError):
+        buildcache('create', '-d', str(tmpdir), '--unsigned')
+
+
 def test_buildcache_create_fail_on_perm_denied(
         install_mockery, mock_fetch, monkeypatch, tmpdir):
     """Ensure that buildcache create fails on permission denied error."""