Raise better exception for Spark master validation

Previously RequiredServiceMissingException was raised for
all cases of invalid count for Spark master, even if the
service was present but count was otherwise incorrect. Now
the correct exception will be raised depending on whether
master is missing or master has wrong count.

Also, add missing unit tests for validation.

Change-Id: Ide7cc8414086e377c86306630920a3c753811458

sahara/plugins/spark/plugin.py

@@ -102,9 +102,13 @@ class SparkProvider(p.ProvisioningPluginBase):
         sm_count = sum([ng.count for ng
                         in utils.get_node_groups(cluster, "master")])
 
-        if sm_count != 1:
+        if sm_count < 1:
             raise ex.RequiredServiceMissingException("Spark master")
 
+        if sm_count >= 2:
+            raise ex.InvalidComponentCountException("Spark master", "1",
+                                                    sm_count)
+
         sl_count = sum([ng.count for ng
                         in utils.get_node_groups(cluster, "slave")])
 

sahara/tests/unit/plugins/spark/test_plugin.py

@@ -20,9 +20,11 @@ from sahara import conductor as cond
 from sahara import context
 from sahara import exceptions as ex
 from sahara.plugins import base as pb
+from sahara.plugins import exceptions as pe
 from sahara.plugins.spark import plugin as pl
 from sahara.service.edp.spark import engine
 from sahara.tests.unit import base
+from sahara.tests.unit import testutils as tu
 from sahara.utils import edp
 
 
@@ -128,6 +130,55 @@ class SparkPluginTest(base.SaharaWithDbTestCase):
             'sudo rm -f /etc/crond.d/spark-cleanup')
 
 
+class SparkValidationTest(base.SaharaTestCase):
+    def setUp(self):
+        super(SparkValidationTest, self).setUp()
+        pb.setup_plugins()
+        self.plugin = pl.SparkProvider()
+
+    def test_validate(self):
+        self.ng = []
+        self.ng.append(tu.make_ng_dict("nn", "f1", ["namenode"], 0))
+        self.ng.append(tu.make_ng_dict("ma", "f1", ["master"], 0))
+        self.ng.append(tu.make_ng_dict("sl", "f1", ["slave"], 0))
+        self.ng.append(tu.make_ng_dict("dn", "f1", ["datanode"], 0))
+
+        self._validate_case(1, 1, 3, 3)
+        self._validate_case(1, 1, 3, 4)
+        self._validate_case(1, 1, 4, 3)
+
+        with testtools.ExpectedException(pe.InvalidComponentCountException):
+            self._validate_case(2, 1, 3, 3)
+
+        with testtools.ExpectedException(pe.InvalidComponentCountException):
+            self._validate_case(1, 2, 3, 3)
+
+        with testtools.ExpectedException(pe.InvalidComponentCountException):
+            self._validate_case(0, 1, 3, 3)
+
+        with testtools.ExpectedException(pe.RequiredServiceMissingException):
+            self._validate_case(1, 0, 3, 3)
+
+        cl = self._create_cluster(
+            1, 1, 3, 3, cluster_configs={'HDFS': {'dfs.replication': 4}})
+
+        with testtools.ExpectedException(pe.InvalidComponentCountException):
+            self.plugin.validate(cl)
+
+    def _create_cluster(self, *args, **kwargs):
+        lst = []
+        for i in range(0, len(args)):
+            self.ng[i]['count'] = args[i]
+            lst.append(self.ng[i])
+
+        return tu.create_cluster("cluster1", "tenant1", "spark",
+                                 "1.60", lst, **kwargs)
+
+    def _validate_case(self, *args):
+        cl = self._create_cluster(*args)
+        self.plugin.validate(cl)
+
+
 class SparkProviderTest(base.SaharaTestCase):
     def setUp(self):
         super(SparkProviderTest, self).setUp()