From 36b126630d44f29cd1a4b681eecc4461ebad56fb Mon Sep 17 00:00:00 2001
From: Maciej Kwiek <mkwiek@mirantis.com>
Date: Tue, 1 Mar 2016 14:05:28 +0100
Subject: [PATCH] Solar orch report doesn't fail for empty graph

Additional message is printed for the case when there are no tasks in
graph to report.

Change-Id: I0074e8e8b0d5a4e25cdb90187790820c4f1c73e0
Closes-bug: 1547537
---
 solar/cli/orch.py                      | 33 ++++++++++++++------------
 solar/orchestration/graph.py           | 10 ++++----
 solar/test/orchestration/test_graph.py | 22 +++++++++++++++++
 3 files changed, 45 insertions(+), 20 deletions(-)
 create mode 100644 solar/test/orchestration/test_graph.py

diff --git a/solar/cli/orch.py b/solar/cli/orch.py
index f53b43d1..ccb49e5e 100755
--- a/solar/cli/orch.py
+++ b/solar/cli/orch.py
@@ -65,22 +65,25 @@ def wait_report(uid, timeout, interval=3):
 
 
 def click_report(uid):
-    colors = {
-        'PENDING': 'cyan',
-        'ERROR': 'red',
-        'SUCCESS': 'green',
-        'INPROGRESS': 'yellow',
-        'SKIPPED': 'blue',
-        'NOOP': 'black'}
-
     report = graph.report_progress(uid)
-    for item in report['tasks']:
-        msg = '{} -> {}'.format(item[0], item[1])
-        if item[2]:
-            msg += ' :: {}'.format(item[2])
-        click.echo(click.style(msg, fg=colors[item[1]]))
-    click.echo('Total Delta: {}'.format(report['total_delta']))
-    click.echo('Total Time: {}'.format(report['total_time']))
+    if len(report['tasks']) == 0:
+        click.echo('Nothing to report')
+    else:
+        colors = {
+            'PENDING': 'cyan',
+            'ERROR': 'red',
+            'SUCCESS': 'green',
+            'INPROGRESS': 'yellow',
+            'SKIPPED': 'blue',
+            'NOOP': 'black'}
+
+        for item in report['tasks']:
+            msg = '{} -> {}'.format(item[0], item[1])
+            if item[2]:
+                msg += ' :: {}'.format(item[2])
+            click.echo(click.style(msg, fg=colors[item[1]]))
+        click.echo('Total Delta: {}'.format(report['total_delta']))
+        click.echo('Total Time: {}'.format(report['total_time']))
 
 
 @orchestration.command()
diff --git a/solar/orchestration/graph.py b/solar/orchestration/graph.py
index 2201fbff..758ff865 100644
--- a/solar/orchestration/graph.py
+++ b/solar/orchestration/graph.py
@@ -103,20 +103,20 @@ def longest_path_time(graph):
     """We are not interested in the path itself, just get the start
     of execution and the end of it.
     """
-    start = None
-    end = None
+    start = float('inf')
+    end = float('-inf')
     for n in graph:
         node_start = graph.node[n]['start_time']
         node_end = graph.node[n]['end_time']
         if node_start is 0.0 or node_end is 0.0:
             continue
 
-        if node_start < start or start is None:
+        if node_start < start:
             start = node_start
 
-        if node_end > end or end is None:
+        if node_end > end:
             end = node_end
-    return end - start
+    return max(end - start, 0.0)
 
 
 def total_delta(graph):
diff --git a/solar/test/orchestration/test_graph.py b/solar/test/orchestration/test_graph.py
new file mode 100644
index 00000000..47d9b091
--- /dev/null
+++ b/solar/test/orchestration/test_graph.py
@@ -0,0 +1,22 @@
+#    Copyright 2016 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import networkx as nx
+
+from solar.orchestration import graph
+
+
+def test_longest_path_time_returns_0_for_empty_graph():
+    g = nx.MultiDiGraph()
+    assert graph.longest_path_time(g) == 0.0