diff --git a/src/test/scala/gitbucket/core/view/HelpersSpec.scala b/src/test/scala/gitbucket/core/view/HelpersSpec.scala
index fc1a2b2..52fa5cf 100644
--- a/src/test/scala/gitbucket/core/view/HelpersSpec.scala
+++ b/src/test/scala/gitbucket/core/view/HelpersSpec.scala
@@ -4,6 +4,8 @@
 import gitbucket.core.service.RepositoryService.RepositoryInfo
 import org.scalatest.FunSpec
 import org.scalatest.mockito.MockitoSugar
+import java.util.Date
+import java.util.TimeZone
 
 class HelpersSpec extends FunSpec with MockitoSugar {
 
@@ -64,4 +66,77 @@
       assert(after == """<a href="http://exa&quot;mple.com">http://exa"mple.com</a>""")
     }
   }
+
+  describe("datetimeAgo") {
+    it("should render a time within a minute") {
+      val time = System.currentTimeMillis()
+      val datetime = datetimeAgo(new Date(time))
+      assert(datetime == "just now")
+    }
+
+    it("should render a time 1 minute ago") {
+      val time = System.currentTimeMillis() - (60 * 1000)
+      val datetime = datetimeAgo(new Date(time))
+      assert(datetime == "1 minute ago")
+    }
+
+    it("should render a time 2 minute ago") {
+      val time = System.currentTimeMillis() - (60 * 1000 * 2)
+      val datetime = datetimeAgo(new Date(time))
+      assert(datetime == "2 minutes ago")
+    }
+  }
+
+  describe("datetimeRFC3339") {
+    it("should format date as RFC3339 format") {
+      val time = 1546961077224L
+      val datetime = datetimeRFC3339(new Date(time))
+      assert(datetime == "2019-01-08T15:24:37Z")
+    }
+  }
+
+  describe("date") {
+    it("should format date as yyyy-MM-dd with default timezone") {
+      val defaultTimeZone = TimeZone.getDefault
+
+      try {
+        val time = 1546961077247L
+        TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+        val datetimeUTC = date(new Date(time))
+        assert(datetimeUTC == "2019-01-08")
+
+        TimeZone.setDefault(TimeZone.getTimeZone("JST"))
+        val datetimeJST = date(new Date(time))
+        assert(datetimeJST == "2019-01-09")
+
+      } finally {
+        TimeZone.setDefault(defaultTimeZone)
+      }
+    }
+  }
+
+  describe("hashDate") {
+    it("should format date as yyyyMMDDHHmmss with default timezone") {
+      val defaultTimeZone = TimeZone.getDefault
+
+      try {
+        val time = 1546961077247L
+        TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+        val hash = hashDate(new Date(time))
+        assert(hash == "20190108152437")
+      } finally {
+        TimeZone.setDefault(defaultTimeZone)
+      }
+    }
+  }
+
+  describe("hashQuery") {
+    it("should return same value for multiple calls") {
+      val time = 1546961077247L
+      val hash1 = hashQuery
+      Thread.sleep(500)
+      val hash2 = hashQuery
+      assert(hash1 == hash2)
+    }
+  }
 }