diff --git a/test-org-contacts.el b/test-org-contacts.el
new file mode 100644
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--- /dev/null
+++ b/test-org-contacts.el
@@ -0,0 +1,53 @@
+(require 'ert)
+
+
+(ert-deftest ert-test-org-contacts-property-email-value-extracting-regexp ()
+  "Testing org-contacts property `EMAIL' value extracting regexp rule."
+  (let ((regexp-rule
+         ;; "\\[\\[mailto:\\(.*\\)\\]\\(\\[.*\\]\\)\\]" ; valid
+         "\\[\\[mailto:\\(.*\\)\\]\\(\\[.*\\]\\)\\]\\(,\\ *\\[\\[mailto:\\(.*\\)\\]\\(\\[.*\\]\\)\\]\\)" ; valid
+         ))
+    (let ((pvalue "huangtc@outlook.com")) ; normal email
+      (if (string-match regexp-rule pvalue)
+          (should (string-equal (match-string 1 pvalue) "yantar92@posteo.net"))
+        pvalue))
+
+    (let ((pvalue "huangtc@outlook.com,")) ; has comma separator
+      (if (string-match regexp-rule pvalue)
+          (should (string-equal (match-string 1 pvalue) "yantar92@posteo.net"))
+        pvalue))
+
+    (let ((pvalue "huangtc@outlook.com, tristan.j.huang@gmail.com,"))
+      (if (string-match regexp-rule pvalue)
+          (should (string-equal (match-string 1 pvalue) "yantar92@posteo.net"))
+        pvalue))
+
+    (let ((pvalue "[[mailto:yantar92@posteo.net]]"))
+      (if (string-match regexp-rule pvalue)
+          (should (string-equal (match-string 1 pvalue) "yantar92@posteo.net"))
+        pvalue))
+
+    (let ((pvalue "[[mailto:yantar92@posteo.net][yantar92@posteo.net]]"))
+      (if (string-match regexp-rule pvalue)
+          (should (string-equal (match-string 1 pvalue) "yantar92@posteo.net"))
+        pvalue))
+
+    (let ((pvalue "[[mailto:yantar92@posteo.net][yantar92@posteo.net]], [[mailto:yantar92@gmail.com][yantar92@gmail.com]]"))
+      (if (string-match regexp-rule pvalue)
+          (should (string-equal (match-string 1 pvalue) "yantar92@posteo.net"))
+        pvalue))
+    ))
+
+;;; literal testing
+
+;; (let ((regexp-rule "\\[\\[mailto:\\(.*\\)\\]\\(\\[.*\\]\\)\\]")
+;;       (pvalue "[[mailto:yantar92@posteo.net][yantar92@posteo.net]]"))
+;;   (if (string-match regexp-rule pvalue)
+;;       (match-string 1 pvalue)
+;;     pvalue))
+
+;; (let ((regexp-rule "\\[\\[mailto:\\(.*\\)\\]\\(\\[.*\\]\\)\\]\\(,\\ *\\[\\[mailto:\\(.*\\)\\]\\(\\[.*\\]\\)\\]\\)")
+;;       (pvalue "[[mailto:yantar92@posteo.net][yantar92@posteo.net]], [[mailto:yantar92@gmail.com][yantar92@gmail.com]]"))
+;;   (if (string-match regexp-rule pvalue)
+;;       (match-string 1 pvalue)
+;;     pvalue))