diff --git a/frontend/device/kobo/nickel_conf.lua b/frontend/device/kobo/nickel_conf.lua
index 97706c6d1..8845a5b85 100644
--- a/frontend/device/kobo/nickel_conf.lua
+++ b/frontend/device/kobo/nickel_conf.lua
@@ -12,6 +12,11 @@ local re_FrontLightLevel = "^FrontLightLevel%s*=%s*(" .. re_BrightnessValue .. "
 local re_PowerOptionsSection = "^%[PowerOptions%]%s*"
 local re_AnySection = "^%[.*%]%s*"
 
+
+function NickelConf._set_kobo_conf_path(new_path)
+    kobo_conf_path = new_path
+end
+
 function NickelConf.frontLightLevel.get()
 
     local new_intensity
@@ -50,8 +55,8 @@ function NickelConf.frontLightLevel.get()
 end
 
 function NickelConf.frontLightLevel.set(new_intensity)
-	assert(new_intensity >= 0 and new_intensity <= 100,
-		"Wrong brightness value given!")
+    assert(new_intensity >= 0 and new_intensity <= 100,
+           "Wrong brightness value given!")
 
     local kobo_conf
     local old_intensity
diff --git a/spec/unit/nickel_conf_spec.lua b/spec/unit/nickel_conf_spec.lua
new file mode 100644
index 000000000..d77340c1f
--- /dev/null
+++ b/spec/unit/nickel_conf_spec.lua
@@ -0,0 +1,135 @@
+require("commonrequire")
+local lfs = require("libs/libkoreader-lfs")
+local NickelConf = require("device/kobo/nickel_conf")
+
+describe("Nickel configuation module", function()
+    describe("Frontlight module", function()
+        it("should read value", function()
+            local fn = os.tmpname()
+            local fd = io.open(fn, "w")
+            fd:write([[
+[OtherThing]
+foo=bar
+[PowerOptions]
+FrontLightLevel=55
+[YetAnotherThing]
+bar=baz
+]])
+            fd:close()
+
+            NickelConf._set_kobo_conf_path(fn)
+            assert.Equals(NickelConf.frontLightLevel.get(), 55)
+
+            os.remove(fn)
+        end)
+
+        it("should create section", function()
+            local fn = os.tmpname()
+            local fd = io.open(fn, "w")
+            fd:write([[
+[OtherThing]
+FrontLightLevel=6
+]])
+            fd:close()
+
+            NickelConf._set_kobo_conf_path(fn)
+            NickelConf.frontLightLevel.set(100)
+
+            fd = io.open(fn, "r")
+            assert.Equals(fd:read("*a"), [[
+[OtherThing]
+FrontLightLevel=6
+[PowerOptions]
+FrontLightLevel=100
+]])
+            fd:close()
+            os.remove(fn)
+
+            fd = io.open(fn, "w")
+            fd:write("")
+            fd:close()
+
+            NickelConf.frontLightLevel.set(20)
+
+            fd = io.open(fn, "r")
+            assert.Equals(fd:read("*a"), [[
+[PowerOptions]
+FrontLightLevel=20
+]])
+            fd:close()
+            os.remove(fn)
+        end)
+
+        it("should replace value", function()
+            local fn = os.tmpname()
+            local fd = io.open(fn, "w")
+            fd:write([[
+[OtherThing]
+foo=bar
+[PowerOptions]
+FrontLightLevel=6
+[YetAnotherThing]
+bar=baz
+]])
+            fd:close()
+
+            NickelConf._set_kobo_conf_path(fn)
+            NickelConf.frontLightLevel.set(100)
+
+            fd = io.open(fn, "r")
+            assert.Equals(fd:read("*a"), [[
+[OtherThing]
+foo=bar
+[PowerOptions]
+FrontLightLevel=100
+[YetAnotherThing]
+bar=baz
+]])
+            fd:close()
+            os.remove(fn)
+        end)
+
+        it("should insert entry", function()
+            local fn = os.tmpname()
+            local fd = io.open(fn, "w")
+            fd:write([[
+[PowerOptions]
+foo=bar
+[OtherThing]
+bar=baz
+]])
+            fd:close()
+
+            NickelConf._set_kobo_conf_path(fn)
+            NickelConf.frontLightLevel.set(1)
+
+            fd = io.open(fn, "r")
+            assert.Equals(fd:read("*a"), [[
+[PowerOptions]
+foo=bar
+FrontLightLevel=1
+[OtherThing]
+bar=baz
+]])
+            fd:close()
+            os.remove(fn)
+        end)
+
+        it("should create config file", function()
+            local fn = "/tmp/abcfoobarbaz449"
+            assert.is_not.Equals(lfs.attributes(fn, "mode"), "file")
+            finally(function() os.remove(fn) end)
+
+            NickelConf._set_kobo_conf_path(fn)
+            NickelConf.frontLightLevel.set(15)
+
+            fd = io.open(fn, "r")
+            assert.Equals([[
+[PowerOptions]
+FrontLightLevel=15
+]],
+                          fd:read("*a"))
+            fd:close()
+        end)
+    end)
+end)