Java: Add script show unit test for basic strings (#2283)

Add script show unit test for basic strings

Signed-off-by: Andrew Carbonetto <andrew.carbonetto@improving.com>

java/client/src/test/java/glide/api/GlideClientTest.java

@@ -1582,6 +1582,27 @@ public void invokeScript_with_ScriptOptionsGlideString_returns_success() {
         assertEquals(payload, response.get());
     }
 
+    @SneakyThrows
+    @Test
+    public void scriptShow_returns_script_source() {
+        // setup
+        String scriptSource = "return { KEYS[1], ARGV[1] }";
+        String hash = UUID.randomUUID().toString();
+
+        CompletableFuture<String> testResponse = new CompletableFuture<>();
+        testResponse.complete(scriptSource);
+
+        when(commandManager.<String>submitNewCommand(eq(ScriptShow), eq(new String[] {hash}), any()))
+                .thenReturn(testResponse);
+
+        // exercise
+        CompletableFuture<String> response = service.scriptShow(hash);
+
+        // verify
+        assertEquals(testResponse, response);
+        assertEquals(scriptSource, response.get());
+    }
+
     @SneakyThrows
     @Test
     public void scriptShow_returns_script_source_glidestring() {