Adds a test script.

Should protect against some of the most rudimentary regressions.

conf.d/sdk.fish

@@ -23,7 +23,7 @@ if test -f "$sdkman_init"
     end
 
     # Declare the sdk command for fish
-    function sdk
+    function sdk -d "Manage SDKs"
         # 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.
@@ -34,7 +34,6 @@ if test -f "$sdkman_init"
 
         set bashPath $bashDump[1]
         set sdkStatus $bashDump[2]
-
         # If SDKMAN! succeeded, copy PATH here (might have changed)
         if [ $sdkStatus = 0 ]
             set newPath (string split : "$bashPath")

test/wrapper.fish

@@ -0,0 +1,40 @@
+set test_commands \
+    "sdk" \
+    "sdk version" \
+    "sdk list java" \
+    "sdk update" \
+    "sdk use ant 1.9.9"
+set test_count (count $test_commands)
+set check_count (math "3 * $test_count")
+
+set sdk_init "$HOME/.sdkman/bin/sdkman-init.sh"
+
+function checksum -a file
+    sha256sum $file | cut -d " " -f 1
+end
+
+echo "Testing the sdk wrapper"
+set failures 0
+for sdk_cmd in $test_commands
+    echo "  Testing '$sdk_cmd'"
+    bash -c "source \"$sdk_init\" && $sdk_cmd > sout_bash; echo \"\$?\" > status_bash; echo "\$PATH" > path_bash"
+    fish -c "$sdk_cmd > sout_fish; echo \"\$status\" > status_fish; echo "\$PATH" > path_fish"
+
+    # Adjust for different path syntax: replace spaces with colons
+    string join : (string split " " (cat path_fish)) > path_fish
+
+    for out in sout status path
+        if [ (checksum "$out"_bash) != (checksum "$out"_fish) ]
+            echo "  - $out bad:"
+            diff "$out"_bash "$out"_fish | sed -e 's/^/    /'
+            set failures (math $failures + 1)
+        else
+            echo "  - $out ok!"
+        end
+    end
+    echo ""
+end
+
+echo "Ran $test_count commands with 3 checks each."
+echo "$failures/$check_count checks failed."
+exit (math $failures != 0)