[#92] Add support for image links

Problem: We should add support for image links.

Solution: Extract image links as regular links.

CHANGES.md

@@ -12,6 +12,8 @@ Unreleased
   + Fixed bug when we reported footnotes as broken links
 * [#163](https://github.com/serokell/xrefcheck/pull/163)
   + Fixed an issue where the progress bar thread might be unexpectedly cancelled and jumble up the output.
+* [#183](https://github.com/serokell/xrefcheck/pull/183)
+  + Add support for image links.
 
 0.2.1
 ==========

src/Xrefcheck/Scanners/Markdown.hs

@@ -243,20 +243,25 @@ nodeExtractInfo fp input@(Node _ _ nSubs) = do
             Nothing -> do
               return mempty
 
-        LINK url _ -> do
-          let rName = nodeExtractText node
-              rPos = toPosition pos
-              link = if null url then rName else url
-          let (rLink, rAnchor) = case T.splitOn "#" link of
-                  [t]    -> (t, Nothing)
-                  t : ts -> (t, Just $ T.intercalate "#" ts)
-                  []     -> error "impossible"
-          return $ FileInfoDiff
-            (DList.singleton $ Reference {rName, rPos, rLink, rAnchor})
-            DList.empty
+        LINK url _ -> extractLink url
+
+        IMAGE url _ -> extractLink url
 
         _ -> return mempty
 
+     where
+       extractLink url = do
+         let rName = nodeExtractText node
+             rPos = toPosition pos
+             link = if null url then rName else url
+         let (rLink, rAnchor) = case T.splitOn "#" link of
+                 [t]    -> (t, Nothing)
+                 t : ts -> (t, Just $ T.intercalate "#" ts)
+                 []     -> error "impossible"
+         return $ FileInfoDiff
+           (DList.singleton $ Reference {rName, rPos, rLink, rAnchor})
+           DList.empty
+
 -- | Check if there is `ignore file` at the beginning of the file,
 -- ignoring preceding comments if there are any.
 checkIgnoreFile :: [Node] -> Bool

tests/golden/check-images/check-images.bats

@@ -0,0 +1,16 @@
+#!/usr/bin/env bats
+
+# SPDX-FileCopyrightText: 2022 Serokell <https://serokell.io>
+#
+# SPDX-License-Identifier: MPL-2.0
+
+load '../helpers/bats-support/load'
+load '../helpers/bats-assert/load'
+load '../helpers/bats-file/load'
+load '../helpers'
+
+@test "Check images" {
+  to_temp xrefcheck -v
+
+  assert_diff expected.gold
+}

tests/golden/check-images/check-images.md

@@ -0,0 +1,29 @@
+<!--
+ - SPDX-FileCopyrightText: 2021 Serokell <https://serokell.io>
+ -
+ - SPDX-License-Identifier: MPL-2.0
+ -->
+
+![good image ref 1](https://avatars.githubusercontent.com/u/13840520 "text")
+
+![good image ref 2][img-ref-good-2]
+
+[img-ref-good-2]: https://avatars.githubusercontent.com/u/13840520 "text"
+
+![good image ref 3](./serokell.png "text")
+
+![good image ref 4][img-ref-good-4]
+
+[img-ref-good-4]: ./serokell.png "text"
+
+
+![bad image ref 1](https://serokell.io/1.png "text")
+
+![bad image ref 2][img-ref-bad-2]
+
+[img-ref-bad-2]: https://serokell.io/2.png "text"
+
+![bad image ref 3](./3.png "text")
+![bad image ref 4][img-ref-bad-4]
+
+[img-ref-bad-4]: ./4.png "text"

tests/golden/check-images/expected.gold

@@ -0,0 +1,82 @@
+=== Repository data ===
+
+  ⮚ check-images.md:
+    - references:
+        - reference (external) at src:7:1-76:
+            - text: "good image ref 1"
+            - link: https://avatars.githubusercontent.com/u/13840520
+            - anchor: -
+        - reference (external) at src:9:1-35:
+            - text: "good image ref 2"
+            - link: https://avatars.githubusercontent.com/u/13840520
+            - anchor: -
+        - reference (relative) at src:13:1-42:
+            - text: "good image ref 3"
+            - link: ./serokell.png
+            - anchor: -
+        - reference (relative) at src:15:1-35:
+            - text: "good image ref 4"
+            - link: ./serokell.png
+            - anchor: -
+        - reference (external) at src:20:1-52:
+            - text: "bad image ref 1"
+            - link: https://serokell.io/1.png
+            - anchor: -
+        - reference (external) at src:22:1-33:
+            - text: "bad image ref 2"
+            - link: https://serokell.io/2.png
+            - anchor: -
+        - reference (relative) at src:26:1-34:
+            - text: "bad image ref 3"
+            - link: ./3.png
+            - anchor: -
+        - reference (relative) at src:27:1-33:
+            - text: "bad image ref 4"
+            - link: ./4.png
+            - anchor: -
+    - anchors: []
+
+
+
+
+=== Invalid references found ===
+
+  ➥  In file check-images.md
+     bad reference (external) at src:20:1-52:
+       - text: "bad image ref 1"
+       - link: https://serokell.io/1.png
+       - anchor: -
+
+     ⛂  Resource unavailable (404 Not Found)
+
+
+  ➥  In file check-images.md
+     bad reference (external) at src:22:1-33:
+       - text: "bad image ref 2"
+       - link: https://serokell.io/2.png
+       - anchor: -
+
+     ⛂  Resource unavailable (404 Not Found)
+
+
+  ➥  In file check-images.md
+     bad reference (relative) at src:26:1-34:
+       - text: "bad image ref 3"
+       - link: ./3.png
+       - anchor: -
+
+     ⛀  File does not exist:
+        3.png
+
+
+  ➥  In file check-images.md
+     bad reference (relative) at src:27:1-33:
+       - text: "bad image ref 4"
+       - link: ./4.png
+       - anchor: -
+
+     ⛀  File does not exist:
+        4.png
+
+
+Invalid references dumped, 4 in total.