Header fixes (#25)

* #21 changing logic to selecting cover image

- For categories, tags

- Some code refactor and indenting

* #21 initial codes for pelican unit tests

* #21 few more testing changes

* Ref #21 unit tests for article tests coverimages

* Ref #21 unit tests for page, tags, category and author coverimages

* Ref #21 readme updated

tests/content/pages/page_with_cover_image.rst

@@ -0,0 +1,7 @@
+:title: Page With Cover Images
+:date: 2018-04-29 00:45
+:author: arul
+:category: foo
+:tags: footag
+:slug: page-with-cover-images
+:cover: assets/images/page_cover.jpg

tests/content/pages/page_with_http_cover_image.rst

@@ -0,0 +1,7 @@
+:title: Page With Cover Images
+:date: 2018-04-29 00:45
+:author: arul
+:category: foo
+:tags: footag
+:slug: page-with-http-cover-images
+:cover: http://example.com/page-cover.jpg

tests/content/pages/page_with_og_image.rst

@@ -0,0 +1,7 @@
+:title: Page With OG Cover Images
+:date: 2018-04-29 00:59
+:author: raj
+:category: bar
+:tags: bartag
+:slug: page-with-og-cover-images
+:og_image: assets/images/og_cover.jpg

tests/content/pages/page_without_cover_image.rst

@@ -0,0 +1,6 @@
+:title: Page Without Cover Images
+:date: 2018-04-29 00:55
+:author: arul
+:category: foo
+:tags: footag
+:slug: page-without-cover-images