From a1811663115ea778f4e73e203cfdc344456486bc Mon Sep 17 00:00:00 2001
From: Brett Smith <brettcsmith@brettcsmith.org>
Date: Tue, 9 May 2017 09:56:08 -0400
Subject: [PATCH] rate: Initial commit.

---
 .gitignore             |  1 +
 oxrlib/__init__.py     |  0
 oxrlib/rate.py         | 47 ++++++++++++++++++++++++++++++++++++++++++
 tests/__init__.py      |  6 ++++++
 tests/historical1.json | 11 ++++++++++
 tests/test_Rate.py     | 23 +++++++++++++++++++++
 6 files changed, 88 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 oxrlib/__init__.py
 create mode 100644 oxrlib/rate.py
 create mode 100644 tests/__init__.py
 create mode 100644 tests/historical1.json
 create mode 100644 tests/test_Rate.py

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c18dd8d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+__pycache__/
diff --git a/oxrlib/__init__.py b/oxrlib/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/oxrlib/rate.py b/oxrlib/rate.py
new file mode 100644
index 0000000..fbbc9cb
--- /dev/null
+++ b/oxrlib/rate.py
@@ -0,0 +1,47 @@
+import datetime
+import functools
+import json
+
+class Rate:
+    FIELDS = [
+        'base',
+        'disclaimer',
+        'license',
+        'rates',
+        'timestamp',
+    ]
+
+    @classmethod
+    def walk_fields(cls, get_field, transform_prefix):
+        for fieldname in cls.FIELDS:
+            value = get_field(fieldname)
+            if value is not None:
+                try:
+                    transformer = getattr(cls, '{}_{}'.format(transform_prefix, fieldname))
+                except AttributeError:
+                    pass
+                else:
+                    value = transformer(value)
+            yield (fieldname, value)
+
+    def __init__(self, base, rates, **kwargs):
+        for key, value in self.walk_fields(kwargs.get, 'deserialize'):
+            setattr(self, key, value)
+        self.base = base
+        self.rates = rates
+
+    @classmethod
+    def deserialize_timestamp(cls, value):
+        return datetime.datetime.fromtimestamp(value)
+
+    @classmethod
+    def serialize_timestamp(cls, value):
+        return int(value.timestamp())
+
+    @classmethod
+    def from_json_file(cls, json_file):
+        response = json.load(json_file)
+        return cls(**response)
+
+    def serialize(self):
+        return dict(self.walk_fields(functools.partial(getattr, self), 'serialize'))
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e3fbdfd
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1,6 @@
+import pathlib
+
+TEST_DIR = pathlib.Path(__file__).parent
+
+def relpath(path):
+    return TEST_DIR / pathlib.Path(path)
diff --git a/tests/historical1.json b/tests/historical1.json
new file mode 100644
index 0000000..b96812d
--- /dev/null
+++ b/tests/historical1.json
@@ -0,0 +1,11 @@
+{
+    "disclaimer": "https://openexchangerates.org/terms/",
+    "license": "https://openexchangerates.org/license/",
+    "timestamp": 982342800,
+    "base": "USD",
+    "rates": {
+        "AED": 3.67246,
+        "ALL": 144.529793,
+        "ANG": 1.79
+    }
+}
diff --git a/tests/test_Rate.py b/tests/test_Rate.py
new file mode 100644
index 0000000..98ebdf9
--- /dev/null
+++ b/tests/test_Rate.py
@@ -0,0 +1,23 @@
+import datetime
+import io
+import json
+
+from . import relpath
+
+import oxrlib.rate
+import pytest
+
+@pytest.fixture
+def historical1_rate():
+    with open(relpath('historical1.json').as_posix()) as rate_file:
+        return oxrlib.rate.Rate.from_json_file(rate_file)
+
+def test_rate_from_json(historical1_rate):
+    assert historical1_rate.base == 'USD'
+    assert historical1_rate.timestamp == datetime.datetime(2001, 2, 16, 12, 0, 0)
+
+def test_serialize(historical1_rate):
+    with open(relpath('historical1.json').as_posix()) as rate_file:
+        expected = json.load(rate_file)
+    assert expected == historical1_rate.serialize()
+