Implementation of the charm state.

state/state_test.go

 // launchpad.net/juju/go/state
 //
 // Copyright (c) 2011-2012 Canonical Ltd.
-
 package state_test
 
 import (
         "fmt"
         . "launchpad.net/gocheck"
         "launchpad.net/gozk/zookeeper"
         "launchpad.net/juju/go/charm"
         "launchpad.net/juju/go/state"
+        "net/url"
+        "path/filepath"
         "testing"
 )
 
-// zkCreate is a simple helper to create a node with a value based
-// on the path. It uses standard parameters for ZooKeeper and the
-// test fails when the node can't be created.
-func zkCreate(c *C, zk *zookeeper.Conn, path, value string) {
-        if _, err := zk.Create(path, value, 0, zookeeper.WorldACL(zookeeper.PERM_ALL)); err != nil {
-                c.Fatal("Cannot set path '"+path+"' in ZooKeeper: ", err)
-        }
+// TestPackage integrates the tests into gotest.
+func TestPackage(t *testing.T) {
+        srv, dir := state.ZkSetUpEnvironment(t)
+        defer state.ZkTearDownEnvironment(t, srv, dir)
+
+        TestingT(t)
 }
 
-// TestPackage integrates the tests into gotest.
-func TestPackage(t *testing.T) {
-        TestingT(t)
+// charmDir returns a directory containing the given test charm.
+func charmDir(name string) string {
+        return filepath.Join("..", "charm", "testrepo", "series", name)
+}
+
+// readCharm returns a test charm by its name.
+func readCharm(c *C, name string) charm.Charm {
+        ch, err := charm.ReadDir(charmDir(name))
+        c.Assert(err, IsNil)
+        return ch
+}
+
+// localCharmURL returns the local URL of a charm.
+func localCharmURL(ch charm.Charm) *charm.URL {
+        url := fmt.Sprintf("local:series/%s-%d", ch.Meta().Name, ch.Revision())
+        return charm.MustParseURL(url)
+}
+
+// addDummyCharm adds the 'dummy' charm state to st.
+func addDummyCharm(c *C, st *state.State) (*state.Charm, *charm.URL) {
+        ch := readCharm(c, "dummy")
+        curl := localCharmURL(ch)
+        bundleURL, err := url.Parse("http://bundle.url")
+        c.Assert(err, IsNil)
+        dummy, err := st.AddCharm(ch, curl, bundleURL)
+        c.Assert(err, IsNil)
+        return dummy, curl
 }
 
 type StateSuite struct {
         zkServer   *zookeeper.Server
         zkTestRoot string
         zkTestPort int
         zkAddr     string
         zkConn     *zookeeper.Conn
         st         *state.State
 }
 
 var _ = Suite(&StateSuite{})
 
-func (s *StateSuite) SetUpSuite(c *C) {
+func (s *StateSuite) SetUpTest(c *C) {
         var err error
-        s.zkTestRoot = c.MkDir() + "/zookeeper"
-        s.zkTestPort = 21812
-        s.zkAddr = fmt.Sprint("localhost:", s.zkTestPort)
-
-        s.zkServer, err = zookeeper.CreateServer(s.zkTestPort, s.zkTestRoot, "")
-        if err != nil {
-                c.Fatal("Cannot set up ZooKeeper server environment: ", err)
-        }
-        err = s.zkServer.Start()
-        if err != nil {
-                c.Fatal("Cannot start ZooKeeper server: ", err)
-        }
-}
-
-func (s *StateSuite) TearDownSuite(c *C) {
-        if s.zkServer != nil {
-                s.zkServer.Destroy()
-        }
-}
-
-func (s *StateSuite) SetUpTest(c *C) {
-        s.st, s.zkConn = state.OpenAddr(c, s.zkAddr)
-        err := s.st.Initialize()
+        s.st, err = state.Open(&state.Info{
+                Addrs: []string{state.ZkAddr},
+        })
         c.Assert(err, IsNil)
+        err = s.st.Initialize()
+        c.Assert(err, IsNil)
+        s.zkConn = state.ZkConn(s.st)
 }
 
 func (s *StateSuite) TearDownTest(c *C) {
         // Delete possible nodes, ignore errors.
         zkRemoveTree(s.zkConn, "/topology")
         zkRemoveTree(s.zkConn, "/charms")
         zkRemoveTree(s.zkConn, "/services")
         zkRemoveTree(s.zkConn, "/machines")
         zkRemoveTree(s.zkConn, "/units")
         zkRemoveTree(s.zkConn, "/relations")
         zkRemoveTree(s.zkConn, "/initialized")
         s.zkConn.Close()
 }
 
+func (s StateSuite) TestAddCharm(c *C) {
+        // Check that adding charms works correctly.
+        dummyCharm := readCharm(c, "dummy")
+        curl := localCharmURL(dummyCharm)
+        bundleURL, err := url.Parse("http://bundle.url")
+        c.Assert(err, IsNil)
+        dummy, err := s.st.AddCharm(dummyCharm, curl, bundleURL)
+        c.Assert(err, IsNil)
+        c.Assert(dummy.URL().String(), Equals, curl.String())
+        _, _, err = s.zkConn.Children("/charms")
+        c.Assert(err, IsNil)
+}
+
+func (s StateSuite) TestCharm(c *C) {
+        // Check that reading a previously added charm works correctly.
+        _, curl := addDummyCharm(c, s.st)
+
+        _, err := s.st.Charm(curl)
+        c.Assert(err, IsNil)
+}
+
+func (s StateSuite) TestCharmAttributes(c *C) {
+        // Check that the basic (invariant) fields of the charm
+        // are correctly in place.
+        _, curl := addDummyCharm(c, s.st)
+
+        dummy, err := s.st.Charm(curl)
+        c.Assert(err, IsNil)
+        c.Assert(dummy.URL().String(), Equals, curl.String())
+        c.Assert(dummy.Revision(), Equals, 1)
+        bundleURL, err := url.Parse("http://bundle.url")
+        c.Assert(err, IsNil)
+        c.Assert(dummy.BundleURL(), DeepEquals, bundleURL)
+        meta := dummy.Meta()
+        c.Assert(meta.Name, Equals, "dummy")
+        config := dummy.Config()
+        c.Assert(config.Options["title"], Equals,
+                charm.Option{
+                        Default:     "My Title",
+                        Description: "A descriptive title used for the service.",
+                        Type:        "string",
+                },
+        )
+}
+
+func (s StateSuite) TestNonExistentCharmPriorToInitialization(c *C) {
+        // Check that getting a charm before any other charm has been added fails nicely.
+        curl, err := charm.ParseURL("local:series/dummy-1")
+        c.Assert(err, IsNil)
+        _, err = s.st.Charm(curl)
+        c.Assert(err, ErrorMatches, `charm not found: "local:series/dummy-1"`)
+}
+
+func (s StateSuite) TestGetNonExistentCharm(c *C) {
+        // Check that getting a non-existent charm fails nicely.
+        addDummyCharm(c, s.st)
+
+        curl := charm.MustParseURL("local:anotherseries/dummy-1")
+        _, err := s.st.Charm(curl)
+        c.Assert(err, ErrorMatches, `charm not found: "local:anotherseries/dummy-1"`)
+}
+
 func (s StateSuite) TestAddService(c *C) {
         // Check that adding services works correctly.
-        charm := state.CharmMock("local:myseries/mytest-1")
-        wordpress, err := s.st.AddService("wordpress", charm)
+        dummy, curl := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         c.Assert(wordpress.Name(), Equals, "wordpress")
-        mysql, err := s.st.AddService("mysql", charm)
+        mysql, err := s.st.AddService("mysql", dummy)
         c.Assert(err, IsNil)
         c.Assert(mysql.Name(), Equals, "mysql")
 
         // Check that retrieving the new created services works correctly.
         wordpress, err = s.st.Service("wordpress")
         c.Assert(err, IsNil)
         c.Assert(wordpress.Name(), Equals, "wordpress")
         url, err := wordpress.CharmURL()
         c.Assert(err, IsNil)
-        c.Assert(url.String(), Equals, "local:myseries/mytest-1")
+        c.Assert(url.String(), Equals, curl.String())
         mysql, err = s.st.Service("mysql")
         c.Assert(err, IsNil)
         c.Assert(mysql.Name(), Equals, "mysql")
         url, err = mysql.CharmURL()
         c.Assert(err, IsNil)
-        c.Assert(url.String(), Equals, "local:myseries/mytest-1")
+        c.Assert(url.String(), Equals, curl.String())
 }
 
 func (s StateSuite) TestRemoveService(c *C) {
-        service, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        service, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
 
         // Check that removing the service works correctly.
         err = s.st.RemoveService(service)
         c.Assert(err, IsNil)
         service, err = s.st.Service("wordpress")
         c.Assert(err, ErrorMatches, `service with name "wordpress" not found`)
 }
 
 func (s StateSuite) TestReadNonExistentService(c *C) {
         _, err := s.st.Service("pressword")
         c.Assert(err, ErrorMatches, `service with name "pressword" not found`)
 }
 
 func (s StateSuite) TestAllServices(c *C) {
         // Check without existing services.
         services, err := s.st.AllServices()
         c.Assert(err, IsNil)
         c.Assert(len(services), Equals, 0)
 
         // Check that after adding services the result is ok.
-        charm := state.CharmMock("local:myseries/mytest-1")
-        _, err = s.st.AddService("wordpress", charm)
+        dummy, _ := addDummyCharm(c, s.st)
+        _, err = s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         services, err = s.st.AllServices()
         c.Assert(err, IsNil)
         c.Assert(len(services), Equals, 1)
 
-        _, err = s.st.AddService("mysql", charm)
+        _, err = s.st.AddService("mysql", dummy)
         c.Assert(err, IsNil)
         services, err = s.st.AllServices()
         c.Assert(err, IsNil)
         c.Assert(len(services), Equals, 2)
 
         // Check the returned service, order is defined by sorted keys.
         c.Assert(services[0].Name(), Equals, "wordpress")
         c.Assert(services[1].Name(), Equals, "mysql")
 }
 
 func (s StateSuite) TestServiceCharm(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, curl := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
 
         // Check that getting and setting the service charm URL works correctly.
-        url, err := wordpress.CharmURL()
+        testcurl, err := wordpress.CharmURL()
         c.Assert(err, IsNil)
-        c.Assert(url.String(), Equals, "local:myseries/mytest-1")
-        url, err = charm.ParseURL("local:myseries/myprod-1")
+        c.Assert(testcurl.String(), Equals, curl.String())
+        testcurl, err = charm.ParseURL("local:myseries/mydummy-1")
         c.Assert(err, IsNil)
-        err = wordpress.SetCharmURL(url)
+        err = wordpress.SetCharmURL(testcurl)
         c.Assert(err, IsNil)
-        url, err = wordpress.CharmURL()
+        testcurl, err = wordpress.CharmURL()
         c.Assert(err, IsNil)
-        c.Assert(url.String(), Equals, "local:myseries/myprod-1")
+        c.Assert(testcurl.String(), Equals, "local:myseries/mydummy-1")
 }
 
 func (s StateSuite) TestServiceExposed(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
 
         // Check that querying for the exposed flag works correctly.
         exposed, err := wordpress.IsExposed()
         c.Assert(err, IsNil)
         c.Assert(exposed, Equals, false)
 
         // Check that setting and clearing the exposed flag works correctly.
         err = wordpress.SetExposed()
         c.Assert(err, IsNil)
@@ skipping 17 matching lines @@
         c.Assert(err, IsNil)
 
         // Check that setting and clearing the exposed flag on removed services also doesn't fail.
         err = s.st.RemoveService(wordpress)
         c.Assert(err, IsNil)
         err = wordpress.ClearExposed()
         c.Assert(err, IsNil)
 }
 
 func (s StateSuite) TestAddUnit(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
 
         // Check that adding units works.
         unitZero, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
         c.Assert(unitZero.Name(), Equals, "wordpress/0")
         unitOne, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
         c.Assert(unitOne.Name(), Equals, "wordpress/1")
 }
 
 func (s StateSuite) TestReadUnit(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         _, err = wordpress.AddUnit()
         c.Assert(err, IsNil)
         _, err = wordpress.AddUnit()
         c.Assert(err, IsNil)
-        mysql, err := s.st.AddService("mysql", state.CharmMock("local:myseries/mytest-1"))
+        mysql, err := s.st.AddService("mysql", dummy)
         c.Assert(err, IsNil)
         _, err = mysql.AddUnit()
         c.Assert(err, IsNil)
 
         // Check that retrieving a unit works correctly.
         unit, err := wordpress.Unit("wordpress/0")
         c.Assert(err, IsNil)
         c.Assert(unit.Name(), Equals, "wordpress/0")
 
         // Check that retrieving a non-existent or an invalidly
         // named unit fail nicely.
         unit, err = wordpress.Unit("wordpress")
         c.Assert(err, ErrorMatches, `"wordpress" is not a valid unit name`)
         unit, err = wordpress.Unit("wordpress/0/0")
         c.Assert(err, ErrorMatches, `"wordpress/0/0" is not a valid unit name`)
         unit, err = wordpress.Unit("pressword/0")
         c.Assert(err, ErrorMatches, `can't find unit "pressword/0" on service "wordpress"`)
         unit, err = wordpress.Unit("mysql/0")
         c.Assert(err, ErrorMatches, `can't find unit "mysql/0" on service "wordpress"`)
 
         // Check that retrieving unit names works.
         unitNames, err := wordpress.UnitNames()
         c.Assert(err, IsNil)
-        c.Assert(unitNames, Equals, []string{"wordpress/0", "wordpress/1"})
+        c.Assert(unitNames, DeepEquals, []string{"wordpress/0", "wordpress/1"})
 
         // Check that retrieving all units works.
         units, err := wordpress.AllUnits()
         c.Assert(err, IsNil)
         c.Assert(len(units), Equals, 2)
         c.Assert(units[0].Name(), Equals, "wordpress/0")
         c.Assert(units[1].Name(), Equals, "wordpress/1")
 }
 
 func (s StateSuite) TestReadUnitWithChangingState(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
 
         // Check that reading a unit after removing the service
         // fails nicely.
         err = s.st.RemoveService(wordpress)
         c.Assert(err, IsNil)
         _, err = s.st.Unit("wordpress/0")
         c.Assert(err, ErrorMatches, `service with name "wordpress" not found`)
 }
 
 func (s StateSuite) TestRemoveUnit(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         _, err = wordpress.AddUnit()
         c.Assert(err, IsNil)
         _, err = wordpress.AddUnit()
         c.Assert(err, IsNil)
 
         // Check that removing a unit works.
         unit, err := wordpress.Unit("wordpress/0")
         c.Assert(err, IsNil)
         err = wordpress.RemoveUnit(unit)
         c.Assert(err, IsNil)
         unitNames, err := wordpress.UnitNames()
         c.Assert(err, IsNil)
-        c.Assert(unitNames, Equals, []string{"wordpress/1"})
+        c.Assert(unitNames, DeepEquals, []string{"wordpress/1"})
 
         // Check that removing a non-existent unit fails nicely.
         err = wordpress.RemoveUnit(unit)
         c.Assert(err, ErrorMatches, "environment state has changed")
 }
 
 func (s StateSuite) TestGetSetPublicAddress(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         unit, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
 
         // Check that retrieving and setting of a public address works.
         address, err := unit.PublicAddress()
         c.Assert(err, ErrorMatches, "unit has no public address")
         err = unit.SetPublicAddress("example.foobar.com")
         c.Assert(err, IsNil)
         address, err = unit.PublicAddress()
         c.Assert(err, IsNil)
         c.Assert(address, Equals, "example.foobar.com")
 }
 
 func (s StateSuite) TestGetSetPrivateAddress(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         unit, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
 
         // Check that retrieving and setting of a private address works.
         address, err := unit.PrivateAddress()
         c.Assert(err, ErrorMatches, "unit has no private address")
         err = unit.SetPrivateAddress("example.local")
         c.Assert(err, IsNil)
         address, err = unit.PrivateAddress()
         c.Assert(err, IsNil)
         c.Assert(address, Equals, "example.local")
 }
 
 func (s StateSuite) TestUnitCharm(c *C) {
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, curl := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         unit, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
 
         // Check that getting and setting the unit charm URL works correctly.
-        url, err := unit.CharmURL()
+        testcurl, err := unit.CharmURL()
         c.Assert(err, IsNil)
-        c.Assert(url.String(), Equals, "local:myseries/mytest-1")
-        url, err = charm.ParseURL("local:myseries/myprod-1")
+        c.Assert(testcurl.String(), Equals, curl.String())
+        testcurl, err = charm.ParseURL("local:myseries/mydummy-1")
         c.Assert(err, IsNil)
-        err = unit.SetCharmURL(url)
+        err = unit.SetCharmURL(testcurl)
         c.Assert(err, IsNil)
-        url, err = unit.CharmURL()
+        testcurl, err = unit.CharmURL()
         c.Assert(err, IsNil)
-        c.Assert(url.String(), Equals, "local:myseries/myprod-1")
+        c.Assert(testcurl.String(), Equals, "local:myseries/mydummy-1")
 }
 
 func (s StateSuite) TestUnassignUnitFromMachineWithoutBeingAssigned(c *C) {
         // When unassigning a machine from a unit, it is possible that
         // the machine has not been previously assigned, or that it
         // was assigned but the state changed beneath us.  In either
         // case, the end state is the intended state, so we simply
         // move forward without any errors here, to avoid having to
         // handle the extra complexity of dealing with the concurrency
         // problems.
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         unit, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
 
         err = unit.UnassignFromMachine()
         c.Assert(err, IsNil)
 
         // Check that the unit has no machine assigned.
         wordpress, err = s.st.Service("wordpress")
         c.Assert(err, IsNil)
         units, err := wordpress.AllUnits()
         c.Assert(err, IsNil)
         unit = units[0]
         _, err = unit.AssignedMachineId()
         c.Assert(err, ErrorMatches, `unit not assigned to machine`)
 }
 
 func (s StateSuite) TestAssignUnitToMachineAgainFails(c *C) {
         // Check that assigning an already assigned unit to
         // a machine fails if it isn't precisely the same
         // machine.·
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         unit, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
         machineOne, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         machineTwo, err := s.st.AddMachine()
         c.Assert(err, IsNil)
 
         err = unit.AssignToMachine(machineOne)
         c.Assert(err, IsNil)
 
         // Assigning the unit to the same machine should return no error.
         err = unit.AssignToMachine(machineOne)
         c.Assert(err, IsNil)
 
         // Assigning the unit to a different machine should fail.
         err = unit.AssignToMachine(machineTwo)
         c.Assert(err, ErrorMatches, `unit "wordpress/0" already assigned to machine 0`)
 
         machineId, err := unit.AssignedMachineId()
         c.Assert(err, IsNil)
         c.Assert(machineId, Equals, 0)
 }
 
 func (s StateSuite) TestUnassignUnitFromMachineWithChangingState(c *C) {
-        // Check
-        wordpress, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        // Check that unassigning while the state changes fails nicely.
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpress, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         unit, err := wordpress.AddUnit()
         c.Assert(err, IsNil)
 
         // Remove the unit for the tests.
         wordpress, err = s.st.Service("wordpress")
         c.Assert(err, IsNil)
         units, err := wordpress.AllUnits()
         c.Assert(err, IsNil)
         unit = units[0]
@@ skipping 12 matching lines @@
         c.Assert(err, ErrorMatches, "environment state has changed")
         _, err = unit.AssignedMachineId()
         c.Assert(err, ErrorMatches, "environment state has changed")
 }
 
 func (s StateSuite) TestAssignUnitToUnusedMachine(c *C) {
         // Create root machine that shouldn't be useds.
         _, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         // Check that a unit can be assigned to an unused machine.
-        mysqlService, err := s.st.AddService("mysql", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        mysqlService, err := s.st.AddService("mysql", dummy)
         c.Assert(err, IsNil)
         mysqlUnit, err := mysqlService.AddUnit()
         c.Assert(err, IsNil)
         mysqlMachine, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         err = mysqlUnit.AssignToMachine(mysqlMachine)
         c.Assert(err, IsNil)
         err = s.st.RemoveService(mysqlService)
         c.Assert(err, IsNil)
 
-        wordpressService, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        wordpressService, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         wordpressUnit, err := wordpressService.AddUnit()
         c.Assert(err, IsNil)
         wordpressMachine, err := wordpressUnit.AssignToUnusedMachine()
         c.Assert(err, IsNil)
 
         c.Assert(wordpressMachine.Id(), Equals, mysqlMachine.Id())
 }
 
 func (s StateSuite) TestAssignUnitToUnusedMachineWithChangingService(c *C) {
         // Create root machine that shouldn't be useds.
         _, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         // Check for a 'state changed' error if a service is manipulated
         // during reuse.
-        mysqlService, err := s.st.AddService("mysql", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        mysqlService, err := s.st.AddService("mysql", dummy)
         c.Assert(err, IsNil)
         mysqlUnit, err := mysqlService.AddUnit()
         c.Assert(err, IsNil)
         mysqlMachine, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         err = mysqlUnit.AssignToMachine(mysqlMachine)
         c.Assert(err, IsNil)
         err = s.st.RemoveService(mysqlService)
         c.Assert(err, IsNil)
 
-        wordpressService, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        wordpressService, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         wordpressUnit, err := wordpressService.AddUnit()
         c.Assert(err, IsNil)
         err = s.st.RemoveService(wordpressService)
         c.Assert(err, IsNil)
 
         _, err = wordpressUnit.AssignToUnusedMachine()
         c.Assert(err, ErrorMatches, "environment state has changed")
 }
 
-func (s StateSuite) TestAssignUniToUnusedMachineWithChangingUnit(c *C) {
+func (s StateSuite) TestAssignUnitToUnusedMachineWithChangingUnit(c *C) {
         // Create root machine that shouldn't be useds.
         _, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         // Check for a 'state changed' error if a unit is manipulated
         // during reuse.
-        mysqlService, err := s.st.AddService("mysql", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        mysqlService, err := s.st.AddService("mysql", dummy)
         c.Assert(err, IsNil)
         mysqlUnit, err := mysqlService.AddUnit()
         c.Assert(err, IsNil)
         mysqlMachine, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         err = mysqlUnit.AssignToMachine(mysqlMachine)
         c.Assert(err, IsNil)
         err = s.st.RemoveService(mysqlService)
         c.Assert(err, IsNil)
 
-        wordpressService, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        wordpressService, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         wordpressUnit, err := wordpressService.AddUnit()
         c.Assert(err, IsNil)
         err = wordpressService.RemoveUnit(wordpressUnit)
         c.Assert(err, IsNil)
 
         _, err = wordpressUnit.AssignToUnusedMachine()
         c.Assert(err, ErrorMatches, "environment state has changed")
 }
 
 func (s StateSuite) TestAssignUnitToUnusedMachineOnlyZero(c *C) {
         // Create root machine that shouldn't be useds.
         _, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         // Check that the unit can't be assigned to machine zero.
-        wordpressService, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        wordpressService, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         wordpressUnit, err := wordpressService.AddUnit()
         c.Assert(err, IsNil)
 
         _, err = wordpressUnit.AssignToUnusedMachine()
         c.Assert(err, ErrorMatches, "no unused machine found")
 }
 
 func (s StateSuite) TestAssignUnitToUnusedMachineNoneAvailable(c *C) {
         // Create machine 0, that shouldn't be used.
         _, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         // Check that assigning without unused machine fails.···
-        mysqlService, err := s.st.AddService("mysql", state.CharmMock("local:myseries/mytest-1"))
+        dummy, _ := addDummyCharm(c, s.st)
+        mysqlService, err := s.st.AddService("mysql", dummy)
         c.Assert(err, IsNil)
         mysqlUnit, err := mysqlService.AddUnit()
         c.Assert(err, IsNil)
         mysqlMachine, err := s.st.AddMachine()
         c.Assert(err, IsNil)
         err = mysqlUnit.AssignToMachine(mysqlMachine)
         c.Assert(err, IsNil)
 
-        wordpressService, err := s.st.AddService("wordpress", state.CharmMock("local:myseries/mytest-1"))
+        wordpressService, err := s.st.AddService("wordpress", dummy)
         c.Assert(err, IsNil)
         wordpressUnit, err := wordpressService.AddUnit()
         c.Assert(err, IsNil)
 
         _, err = wordpressUnit.AssignToUnusedMachine()
         c.Assert(err, ErrorMatches, "no unused machine found")
 }
 
 // zkRemoveTree recursively removes a tree.
 func zkRemoveTree(zk *zookeeper.Conn, path string) error {
         // First recursively delete the children.
         children, _, err := zk.Children(path)
         if err != nil {
                 return err
         }
         for _, child := range children {
                 if err = zkRemoveTree(zk, fmt.Sprintf("%s/%s", path, child)); err != nil {
                         return err
                 }
         }
         // Now delete the path itself.
         return zk.Delete(path, -1)
 }