adding more unit tests, bug fixes and code cleanup

Author: chris-hoefgen

src/main/java/com/devcycle/sdk/server/local/api/DVCLocalClient.java

@@ -119,9 +119,9 @@ public <T> Variable<T> variable(User user, String key, T defaultValue) {
       }
       return defaultVariable;
     }
-
+    String variableJSON = null;
     try {
-      String variableJSON = localBucketing.getVariable(sdkKey, user, key, variableType, true);
+      variableJSON = localBucketing.getVariable(sdkKey, user, key, variableType, true);
       if (variableJSON == null || variableJSON.isEmpty()) {
         return defaultVariable;
       } else {
@@ -137,12 +137,14 @@ public <T> Variable<T> variable(User user, String key, T defaultValue) {
                 .build();
         if (variable.getType() != variableType) {
           System.out.printf("Variable type mismatch, returning default value");
-          return variable;
+          return defaultVariable;
         }
         variable.setDefaultValue(defaultValue);
         variable.setIsDefaulted(false);
         return variable;
       }
+    } catch(JsonProcessingException jpe){
+      System.out.printf("Unable to parse load Variable %s due to JSON error: err=%s, data=", key, jpe.getMessage(), variableJSON);
     } catch (Exception e) {
       System.out.printf("Unable to parse load Variable %s due to error: %s", key, e);
     }
@@ -199,8 +201,10 @@ public void close() {
     if (!isInitialized) {
       return;
     }
-    configManager.cleanup();
-    eventQueueManager.cleanup();
+    if (configManager != null)
+      configManager.cleanup();
+    if(eventQueueManager != null)
+      eventQueueManager.cleanup();
   }
 
   private void validateUser(User user) {

src/main/java/com/devcycle/sdk/server/local/bucketing/LocalBucketing.java

@@ -191,6 +191,9 @@ public String getVariable(String sdkKey, User user, String key, Variable.TypeEnu
                 store, getVariablePtr, I32, I32, I32, I32, I32, I32);
 
         int resultAddress = variableForUser.call(sdkKeyAddress, userAddress, keyAddress, wasmVariableType, shouldTrackEvent ? 1 : 0);
+        if (resultAddress == 0){
+            return null;
+        }
         String variableString = readWasmString(resultAddress);
         return variableString;
     }

src/test/java/com/devcycle/sdk/server/local/DVCLocalClientTest.java

@@ -50,12 +50,72 @@ public void variableTest() {
         User user = getUser();
         user.setEmail("giveMeVariationOff@email.com");
         Variable<String> var = client.variable(user, "string-var", "default string");
+        Assert.assertNotNull(var);
         Assert.assertEquals("variationOff", var.getValue());
 
         user.setEmail("giveMeVariationOn@email.com");
         var = client.variable(user, "string-var", "default string");
+        Assert.assertNotNull(var);
         Assert.assertEquals("variationOn", var.getValue());
     }
+    @Test
+    public void variableTestNotInitialized(){
+        // NOTE  - this test will generate some additional logging noise from the EventQueue
+        // because it isn't initialized properly before the first call to variable()
+        DVCLocalClient client = new DVCLocalClient(apiKey);
+        Variable<String> var = client.variable(getUser(), "string-var", "default string");
+        Assert.assertNotNull(var);
+        Assert.assertTrue(var.getIsDefaulted());
+        Assert.assertEquals("default string", var.getValue());
+    }
+
+    @Test
+    public void variableTestUnknownVariableKey(){
+        Variable<Boolean> var = client.variable(getUser(), "some-var-that-doesnt-exist", true);
+        Assert.assertNotNull(var);
+        Assert.assertTrue(var.getIsDefaulted());
+        Assert.assertEquals(true, var.getValue());
+    }
+
+    @Test
+    public void variableTestTypeMismatch(){
+        Variable<Boolean> var = client.variable(getUser(), "string-var", true);
+        Assert.assertNotNull(var);
+        Assert.assertTrue(var.getIsDefaulted());
+        Assert.assertEquals(true, var.getValue());
+    }
+
+    @Test
+    public void variableTestNoDefault() {
+        User user = getUser();
+        try {
+            Variable<String> var = client.variable(user, "string-var", null);
+            Assert.fail("Expected IllegalArgumentException for null default value");
+        }catch(IllegalArgumentException e) {
+            // expected
+        }
+    }
+
+    @Test
+    public void variableTestNullUser() {
+        try{
+            client.variable(null, "string-var", "default string");
+            Assert.fail("Expected IllegalArgumentException for null user");
+        }catch(IllegalArgumentException e) {
+            // expected
+        }
+    }
+
+    @Test
+    public void variableTestBadUserID() {
+        User badUser = User.builder().userId("").build();
+        try {
+            client.variable(badUser, "string-var", "default string");
+            Assert.fail("Expected IllegalArgumentException for empty userID");
+        }catch(IllegalArgumentException e) {
+            // expected
+        }
+    }
 
     @Test
     public void variableValueTest() {