add visibility handling for the floating window

tests/test_samurai_output_spec.lua

@@ -0,0 +1,19 @@
+local test_samurai = require("test-samurai")
+local core = require("test-samurai.core")
+
+describe("test-samurai output API", function()
+  it("delegates show_output to core", function()
+    local called = false
+    local orig = core.show_output
+
+    core.show_output = function()
+      called = true
+    end
+
+    test_samurai.show_output()
+
+    core.show_output = orig
+
+    assert.is_true(called)
+  end)
+end)