Refactoring: bash calling in its own function.

Also:
 - Fixes Travis build reg. bf13d2f.
 - Wrapper test now cleans up after itself.

functions/sdk.fish

@@ -5,14 +5,16 @@ if not test -f "$sdkman_init"
   exit 0
 end
 
-# Declare the sdk command for fish
-function sdk -d "Manage SDKs"
+# Runs the given command in bash, capturing some side effects
+# and repeating them on the current fish shell.
+# Returns the same status code as the given command.
+function __fish_sdkman_run_in_bash
     # We need to leave stdin and stdout of sdk free for user interaction.
     # So, pipe PATH (which might have changed) through a file.
     # Now, getting the exit code of sdk itself is a hassle so pipe it as well.
     # TODO: Can somebody get this to work without the overhead of a file?
     set pipe (mktemp)
-    bash -c "source $sdkman_init && sdk $argv; echo -e \"\$PATH\n\$?\" > $pipe"
+    bash -c "$argv[1]; echo -e \"\$PATH\n\$?\" > $pipe"
     set bashDump (cat $pipe; rm $pipe)
 
     set bashPath $bashDump[1]
@@ -24,4 +26,9 @@ function sdk -d "Manage SDKs"
     end
 
     return $sdkStatus
+end
+
+# Declare the sdk command for fish
+function sdk -d "Manage SDKs"
+    __fish_sdkman_run_in_bash "source $sdkman_init && sdk $argv"
 end