Nothing comparison improvement (#741)

* improve nothing comparison

* rollback not nothing comarison

Author: AtsushiSakai

src/download.jl

@@ -22,10 +22,10 @@ function try_get_filename_from_headers(resp)
         # extract out of Content-Disposition line
         # rough version of what is needed in https://github.com/JuliaWeb/HTTP.jl/issues/179
         filename_part = match(r"filename\s*=\s*(.*)", content_disp)
-        if filename_part != nothing
+        if filename_part !== nothing
             filename = filename_part[1]
             quoted_filename = match(r"\"(.*)\"", filename)
-            if quoted_filename != nothing
+            if quoted_filename !== nothing
                 # It was in quotes, so it will be double escaped
                 filename = unescape_string(quoted_filename[1])
             end

test/utils.jl

@@ -37,14 +37,14 @@ import HTTP.URIs
     end
 
     withenv("HTTPS_PROXY"=>nothing, "https_proxy"=>nothing) do
-        @test HTTP.ConnectionRequest.getproxy("https", "https://julialang.org/") == nothing
+        @test HTTP.ConnectionRequest.getproxy("https", "https://julialang.org/") === nothing
     end
     withenv("HTTPS_PROXY"=>"") do
         # to be compatible with Julia 1.0
-        @test HTTP.ConnectionRequest.getproxy("https", "https://julialang.org/") == nothing
+        @test HTTP.ConnectionRequest.getproxy("https", "https://julialang.org/") === nothing
     end
     withenv("https_proxy"=>"") do
-        @test HTTP.ConnectionRequest.getproxy("https", "https://julialang.org/") == nothing
+        @test HTTP.ConnectionRequest.getproxy("https", "https://julialang.org/") === nothing
     end
     withenv("HTTPS_PROXY"=>"https://user:pass@server:80") do
         @test HTTP.ConnectionRequest.getproxy("https", "https://julialang.org/") == "https://user:pass@server:80"
@@ -54,13 +54,13 @@ import HTTP.URIs
     end
 
     withenv("HTTP_PROXY"=>nothing, "http_proxy"=>nothing) do
-        @test HTTP.ConnectionRequest.getproxy("http", "http://julialang.org/") == nothing
+        @test HTTP.ConnectionRequest.getproxy("http", "http://julialang.org/") === nothing
     end
     withenv("HTTP_PROXY"=>"") do
-        @test HTTP.ConnectionRequest.getproxy("http", "http://julialang.org/") == nothing
+        @test HTTP.ConnectionRequest.getproxy("http", "http://julialang.org/") === nothing
     end
     withenv("http_proxy"=>"") do
-        @test HTTP.ConnectionRequest.getproxy("http", "http://julialang.org/") == nothing
+        @test HTTP.ConnectionRequest.getproxy("http", "http://julialang.org/") === nothing
     end
     withenv("HTTP_PROXY"=>"http://user:pass@server:80") do
         @test HTTP.ConnectionRequest.getproxy("http", "http://julialang.org/") == "http://user:pass@server:80"