From 20db9552ccb2fce44c6adad996692c45c5c0f6cc Mon Sep 17 00:00:00 2001
From: Brian Bazurto <124537281+ba-00001@users.noreply.github.com>
Date: Sat, 27 Jun 2026 17:04:22 -0500
Subject: [PATCH] Fix confirmout.json handling for missing/malformed files
 (#16)

The confirmout.json loader logged "JSON is in wrong format" whenever the
file was simply absent, and would NPE if the file existed but failed to
parse (the IOException was caught but rootDevNode was still dereferenced).

Report a clear "not found" message when the file is missing, return
early after a parse failure instead of dereferencing null, and extract
the loading logic into a testable method. Add unit tests for the
missing, null, malformed, and valid cases.
---
 .../entities/DeviceErrorStatusResponse.java   | 37 +++++++-----
 .../DeviceErrorStatusResponseTest.java        | 58 +++++++++++++++++++
 2 files changed, 79 insertions(+), 16 deletions(-)
 create mode 100644 src/test/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponseTest.java

diff --git a/src/main/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponse.java b/src/main/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponse.java
index bcc5ae2..7a721fb 100644
--- a/src/main/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponse.java
+++ b/src/main/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponse.java
@@ -20,24 +20,29 @@ public class DeviceErrorStatusResponse {
     private static List<DeviceErrorStatus> deviceErrorStatuses;
 
     private DeviceErrorStatusResponse(){
-        deviceErrorStatuses = new CopyOnWriteArrayList<>();
-        ObjectMapper objectMapper = new ObjectMapper();
-        File jsonConfirm = new File("/var/tmp/CONFIRMOUT/confirmout.json");
-        if(jsonConfirm.exists() && jsonConfirm.isFile()){
-            JsonNode rootDevNode = null;
-            try {
-                rootDevNode = objectMapper.readTree(jsonConfirm);
-            } catch (IOException ioException) {
-                log.failure("Error in parsing confirmout", 17, ioException);
-            }
-            Iterator<String> fieldNames = rootDevNode.fieldNames();
+        deviceErrorStatuses = loadDeviceErrorStatuses(new File("/var/tmp/CONFIRMOUT/confirmout.json"));
+    }
 
-            while(fieldNames.hasNext()){
-                deviceErrorStatuses.add(new DeviceErrorStatus(fieldNames.next(), false, null));
-            }
-        } else {
-            log.failure("JSON is in wrong format", 17, null);
+    static List<DeviceErrorStatus> loadDeviceErrorStatuses(File jsonConfirm){
+        List<DeviceErrorStatus> statuses = new CopyOnWriteArrayList<>();
+        if(jsonConfirm == null || !jsonConfirm.exists() || !jsonConfirm.isFile()){
+            log.failure("confirmout.json not found at " + (jsonConfirm == null ? "null" : jsonConfirm.getPath()), 17, null);
+            return statuses;
+        }
+
+        JsonNode rootDevNode;
+        try {
+            rootDevNode = new ObjectMapper().readTree(jsonConfirm);
+        } catch (IOException ioException) {
+            log.failure("JSON is in wrong format", 17, ioException);
+            return statuses;
+        }
+
+        Iterator<String> fieldNames = rootDevNode.fieldNames();
+        while(fieldNames.hasNext()){
+            statuses.add(new DeviceErrorStatus(fieldNames.next(), false, null));
         }
+        return statuses;
     }
 
     public static List<DeviceErrorStatus> getDeviceErrorStatusResponse(){
diff --git a/src/test/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponseTest.java b/src/test/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponseTest.java
new file mode 100644
index 0000000..1edf94a
--- /dev/null
+++ b/src/test/java/com/target/devicemanager/common/entities/DeviceErrorStatusResponseTest.java
@@ -0,0 +1,58 @@
+package com.target.devicemanager.common.entities;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class DeviceErrorStatusResponseTest {
+
+    @TempDir
+    Path tempDir;
+
+    @Test
+    public void loadDeviceErrorStatuses_WhenFileMissing_ReturnsEmptyList() {
+        File missing = tempDir.resolve("confirmout.json").toFile();
+
+        List<DeviceErrorStatus> result = DeviceErrorStatusResponse.loadDeviceErrorStatuses(missing);
+
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    public void loadDeviceErrorStatuses_WhenNull_ReturnsEmptyList() {
+        List<DeviceErrorStatus> result = DeviceErrorStatusResponse.loadDeviceErrorStatuses(null);
+
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    public void loadDeviceErrorStatuses_WhenMalformedJson_ReturnsEmptyListWithoutThrowing() throws IOException {
+        File bad = tempDir.resolve("confirmout.json").toFile();
+        Files.writeString(bad.toPath(), "{ this is not valid json ");
+
+        List<DeviceErrorStatus> result = DeviceErrorStatusResponse.loadDeviceErrorStatuses(bad);
+
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    public void loadDeviceErrorStatuses_WhenValidJson_ReturnsADeviceStatusPerTopLevelField() throws IOException {
+        File good = tempDir.resolve("confirmout.json").toFile();
+        Files.writeString(good.toPath(), "{\"scanner\":{},\"printer\":{}}");
+
+        List<DeviceErrorStatus> result = DeviceErrorStatusResponse.loadDeviceErrorStatuses(good);
+
+        assertEquals(2, result.size());
+        assertEquals("scanner", result.get(0).deviceName);
+        assertEquals("printer", result.get(1).deviceName);
+        assertTrue(result.stream().noneMatch(status -> status.faultPresent));
+    }
+}