Fix link creation failing on empty text

lua/zettelkasten/link.lua

@@ -23,6 +23,7 @@ end
 -- Returns text with surrounding whitespace trimmed. Returns empty string
 -- if only whitespace.
 local function trimmed(text)
+    if not text then return end
     return text:match '^()%s*$' and '' or text:match '^%s*(.*%S)'
 end
 
@@ -45,7 +46,8 @@ function L.style_wiki(link, text)
     return "[[" .. link .. pipe .. "]]"
 end
 
--- Returns a correctly formatted link to a new zettel.
+-- Returns a correctly formatted link to a zettel.
+-- Requires an anchor to be passed in.
 -- Takes an optional link text which will be added to the link.
 -- Takes an optional style according to which the link will be transformed.
 function L.create(anchor, text, style)

lua/zettelkasten/link_spec.lua

@@ -61,7 +61,7 @@ describe("style_wiki", function()
     end)
 end)
 
-describe("create_link", function()
+describe("create", function()
     it("should create a working link using set options in vim", function()
         vim.g.zettel_extension = ".md"
         vim.g.zettel_anchor_separator = "_"
@@ -76,4 +76,10 @@ describe("create_link", function()
         assert.same("[[1910291645|My FILE NAME]]",
                     link.create("1910291645", "My FILE NAME", "wiki"))
     end)
+    it("should handle empty text", function()
+        vim.g.zettel_extension = ".wiki"
+        vim.g.zettel_anchor_separator = "_"
+        vim.g.zettel_link_style = "wiki"
+        assert.same("[[1910291645]]", link.create("1910291645"))
+    end)
 end)