Adds integration tests and polish:

- Adds constants for columns name and other repeatedly used strings
- Adds a reordering df columns function (also fixes column order inconsistencies)
- Changes period AAI from sum to average
- Fixes bugs when group_id not defined (also now returns None instead of empty df
- Adds convenience function in Snapshot for ImpactCalc init
- Now sorts snapshots list by date in base class
- Now allows None for risk_disc_rates

Author: spjuhel

climada/test/test_trajectories.py

@@ -0,0 +1,55 @@
+"""
+This file is part of CLIMADA.
+
+Copyright (C) 2017 ETH Zurich, CLIMADA contributors listed in AUTHORS.
+
+CLIMADA is free software: you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free
+Software Foundation, version 3.
+
+CLIMADA is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with CLIMADA. If not, see <https://www.gnu.org/licenses/>.
+
+---
+
+Define constants for trajectories module.
+"""
+
+DEFAULT_TIME_RESOLUTION = "Y"
+DATE_COL_NAME = "date"
+PERIOD_COL_NAME = "period"
+GROUP_COL_NAME = "group"
+GROUP_ID_COL_NAME = "group_id"
+MEASURE_COL_NAME = "measure"
+NO_MEASURE_VALUE = "no_measure"
+METRIC_COL_NAME = "metric"
+UNIT_COL_NAME = "unit"
+RISK_COL_NAME = "risk"
+COORD_ID_COL_NAME = "coord_id"
+
+DEFAULT_PERIOD_INDEX_NAME = "date"
+
+DEFAULT_RP = [20, 50, 100]
+"""Default return periods to use when computing return period impact estimates."""
+
+DEFAULT_ALLGROUP_NAME = "All"
+"""Default string to use to define the exposure subgroup containing all exposure points."""
+
+EAI_METRIC_NAME = "eai"
+AAI_METRIC_NAME = "aai"
+AAI_PER_GROUP_METRIC_NAME = "aai_per_group"
+CONTRIBUTIONS_METRIC_NAME = "risk_contributions"
+RETURN_PERIOD_METRIC_NAME = "return_periods"
+RP_VALUE_PREFIX = "rp"
+
+
+CONTRIBUTION_BASE_RISK_NAME = "base risk"
+CONTRIBUTION_TOTAL_RISK_NAME = "total risk"
+CONTRIBUTION_EXPOSURE_NAME = "exposure contribution"
+CONTRIBUTION_HAZARD_NAME = "hazard contribution"
+CONTRIBUTION_VULNERABILITY_NAME = "vulnerability contribution"
+CONTRIBUTION_INTERACTION_TERM_NAME = "interaction contribution"