Fix postgres template syntax and parameter output (#304)

- Use correct `.key?` syntax, Fix #300
- Emit correct boolean, introduced in #278
- Add postgres spec test

Closes #302

Signed-off-by: Mike Fiedler <miketheman@gmail.com>

spec/integrations/postgres_spec.rb

@@ -0,0 +1,57 @@
+describe 'datadog::postgres' do
+  expected_yaml = <<-EOF
+    instances:
+    - host: localhost
+      port: 5432
+      ssl: true
+      username: datadog
+      password: somepass
+      dbname: my_database
+      tags:
+      - spec
+      relations:
+      - apple_table
+      - orange_table
+      collect_function_metrics: true
+    init_config:
+  EOF
+
+  cached(:chef_run) do
+    ChefSpec::SoloRunner.new(step_into: ['datadog_monitor']) do |node|
+      node.automatic['languages'] = { python: { version: '2.7.2' } }
+
+      node.set['datadog'] = {
+        api_key: 'someapikey',
+        postgres: {
+          instances: [
+            {
+              collect_function_metrics: true,
+              dbname: 'my_database',
+              password: 'somepass',
+              port: 5432,
+              relations: ['apple_table', 'orange_table'],
+              server: 'localhost',
+              ssl: true,
+              tags: ['spec'],
+              username: 'datadog'
+            }
+          ]
+        }
+      }
+    end.converge(described_recipe)
+  end
+
+  subject { chef_run }
+
+  it_behaves_like 'datadog-agent'
+
+  it { is_expected.to include_recipe('datadog::dd-agent') }
+
+  it { is_expected.to add_datadog_monitor('postgres') }
+
+  it 'renders expected YAML config file' do
+    expect(chef_run).to render_file('/etc/dd-agent/conf.d/postgres.yaml').with_content { |content|
+      expect(YAML.load(content).to_json).to be_json_eql(YAML.load(expected_yaml).to_json)
+    }
+  end
+end

templates/default/postgres.yaml.erb

@@ -25,7 +25,7 @@ instances:
       - <%= r %>
         <% end -%>
     <% end -%>
-    <% if i.keys?("collect_function_metrics") -%>
-    collect_function_metrics: i["collect_function_metrics"]
+    <%- if i.key?("collect_function_metrics") %>
+    collect_function_metrics: <%= i["collect_function_metrics"] %>
     <% end -%>
 <% end -%>