Handle Faraday::ServerError (for example 502) as HTTPFailure

closes #8380

Changelog.md

@@ -12,6 +12,7 @@
 * Update the suggested Ruby version to 2.7. If you run into trouble during the update and you followed our installation guides, run `rvm install 2.7`. [#8366](https://github.com/diaspora/diaspora/pull/8366)
 * Upgrade to bundler 2 [#8366](https://github.com/diaspora/diaspora/pull/8366)
 * Stop checking `/.well-known/host-meta`, check for `/.well-known/nodeinfo` instead [#8377](https://github.com/diaspora/diaspora/pull/8377)
+* Handle NodeInfo timeouts gracefully [#8380](https://github.com/diaspora/diaspora/pull/8380)
 
 ## Bug fixes
 * Fix that no mails were sent after photo export [#8365](https://github.com/diaspora/diaspora/pull/8365)

lib/connection_tester.rb

@@ -109,7 +109,7 @@ class ConnectionTester
     raise NetFailure, e.message
   rescue Faraday::SSLError => e
     raise SSLFailure, e.message
-  rescue ArgumentError, Faraday::ClientError => e
+  rescue ArgumentError, Faraday::ClientError, Faraday::ServerError => e
     raise HTTPFailure, "#{e.class}: #{e.message}"
   rescue StandardError => e
     unexpected_error(e)

spec/lib/connection_tester_spec.rb

@@ -94,6 +94,11 @@ describe ConnectionTester do
       expect { tester.request }.to raise_error(ConnectionTester::HTTPFailure)
     end
 
+    it "receives a 502 bad gateway" do
+      stub_request(:get, url).to_return(status: 502, body: "Bad Gateway!")
+      expect { tester.request }.to raise_error(ConnectionTester::HTTPFailure)
+    end
+
     it "cannot connect" do
       stub_request(:get, url).to_raise(Faraday::ConnectionFailed.new("Error!"))
       expect { tester.request }.to raise_error(ConnectionTester::NetFailure)