710 Bugfix escape char func (#772)

* Fix escape_char for quote

The `"` need no escaping. The old version, which was introduced in this
[commit](ea03412#diff-5a72a6018b10915bef41b81020b59395527ba5b4b844d222b4e97192b5450565R369),
has unexpected behaviour of adding a `\` in the resulting strings.

This change fixes this issue.

* Add plenary test for escape_cahr()

Not sure about the style guide for plenary tests. So added it here.

Further, I think one should perhaps add more special cahracters to the
test for not changing characters, but not sure what the expected
coverage of the test should be.

* Fix stylua formatting

---------

Co-authored-by: Will Dean <[email protected]>

lua/octo/utils.lua

@@ -748,8 +748,7 @@ end
 
 --- Escapes a characters on a string to be used as a JSON string
 function M.escape_char(string)
-  return string.gsub(string, '["\\]', {
-    ['"'] = '\\"',
+  return string.gsub(string, "[\\]", {
     ["\\"] = "\\\\",
   })
 end

lua/tests/plenary/utils_spec.lua

@@ -47,3 +47,23 @@ describe("Utils module:", function()
     end)
   end)
 end)
+
+describe("Utils escape_char(): ", function()
+  it("escapes backslash characters in a string", function()
+    local input = [[hello \\ world]]
+    local expected = [[hello \\\\ world]]
+    eq(expected, this.escape_char(input))
+  end)
+
+  it("returns the same string if no escape characters", function()
+    local input = [['hello/ ~^'*$"world%]]
+    local expected = [['hello/ ~^'*$"world%]]
+    eq(expected, this.escape_char(input))
+  end)
+
+  it("handles an empty string", function()
+    local input = ""
+    local expected = ""
+    eq(expected, this.escape_char(input))
+  end)
+end)