(tests): add test for headline extraction (#840)

tests/roam-files/headlines/headline.org

@@ -0,0 +1,14 @@
+#+TITLE: Headline
+
+* Headline 1
+:PROPERTIES:
+:ID:       e84d0630-efad-4017-9059-5ef917908823
+:END:
+
+* No headline here
+Oops.
+
+* Headline 2
+:PROPERTIES:
+:ID:       801b58eb-97e2-435f-a33e-ff59a2f0c213
+:END:

tests/test-org-roam.el

@@ -225,6 +225,26 @@
                 :to-equal
                 '("t1" "t2 with space" "t3" "tags"))))))
 
+(describe "Headline extraction"
+  (before-all
+    (test-org-roam--init))
+
+  (after-all
+    (test-org-roam--teardown))
+
+  (cl-flet
+      ((test (fn file)
+             (let* ((fname (test-org-roam--abs-path file))
+                    (buf (find-file-noselect fname)))
+               (with-current-buffer buf
+                 (funcall fn fname)))))
+    (it "extracts headlines"
+      (expect (test #'org-roam--extract-headlines
+                    "headlines/headline.org")
+              :to-equal
+              `(["e84d0630-efad-4017-9059-5ef917908823" ,(test-org-roam--abs-path "headlines/headline.org")]
+                ["801b58eb-97e2-435f-a33e-ff59a2f0c213" ,(test-org-roam--abs-path "headlines/headline.org")])))))
+
 ;;; Tests
 (xdescribe "org-roam-db-build-cache"
   (before-each