diff --git a/src/helper/assertionUtils.js b/src/helper/assertionUtils.js
index 2ec2645..1e9214f 100644
--- a/src/helper/assertionUtils.js
+++ b/src/helper/assertionUtils.js
@@ -16,7 +16,7 @@ class Assertions {
     assertNoNaN(arr, label = "array") {
         if (Array.isArray(arr)) {
             for (const el of arr) {
-                assertNoNaN(el, label);
+                this.assertNoNaN(el, label);
             }
         } else {
             if (Number.isNaN(arr)) {
@@ -26,4 +26,4 @@ class Assertions {
     }
 }
 
-module.exports = Assertions;
\ No newline at end of file
+module.exports = Assertions;
diff --git a/src/helper/configUtils.js b/src/helper/configUtils.js
index e81d1d5..58cb334 100644
--- a/src/helper/configUtils.js
+++ b/src/helper/configUtils.js
@@ -39,8 +39,8 @@ const Logger = require("./logger");
 
 class ConfigUtils {
     constructor(defaultConfig, IloggerEnabled , IloggerLevel) {
-        const loggerEnabled = IloggerEnabled || true;
-        const loggerLevel = IloggerLevel || "warn";
+        const loggerEnabled = IloggerEnabled ?? true;
+        const loggerLevel = IloggerLevel ?? "warn";
         this.logger = new Logger(loggerEnabled, loggerLevel, 'ConfigUtils');
         this.defaultConfig = defaultConfig;
         this.validationUtils = new ValidationUtils(loggerEnabled, loggerLevel);
diff --git a/src/helper/logger.js b/src/helper/logger.js
index 8b4f696..3c2f15b 100644
--- a/src/helper/logger.js
+++ b/src/helper/logger.js
@@ -44,7 +44,7 @@ class Logger {
       if (this.levels.includes(level)) {
         this.logLevel = level;
       } else {
-        console.error(`[ERROR ${nameModule}]: Invalid log level: ${level}`);
+        console.error(`[ERROR] -> ${this.nameModule}: Invalid log level: ${level}`);
       }
     }
   
@@ -54,4 +54,4 @@ class Logger {
     }
   }
   
-  module.exports = Logger;
\ No newline at end of file
+  module.exports = Logger;
diff --git a/src/helper/validationUtils.js b/src/helper/validationUtils.js
index ddbba58..c442d59 100644
--- a/src/helper/validationUtils.js
+++ b/src/helper/validationUtils.js
@@ -36,8 +36,8 @@ const Logger = require("./logger");
 
 class ValidationUtils {
   constructor(IloggerEnabled, IloggerLevel) {
-        const loggerEnabled = IloggerEnabled || true;
-        const loggerLevel = IloggerLevel || "warn";
+        const loggerEnabled = IloggerEnabled ?? true;
+        const loggerLevel = IloggerLevel ?? "warn";
         this.logger = new Logger(loggerEnabled, loggerLevel, 'ValidationUtils');
   }
 
@@ -191,7 +191,7 @@ class ValidationUtils {
               continue;
             }
 
-            if("default" in v){
+            if(v && typeof v === "object" && "default" in v){
                 //put the default value in the object
                 newObj[k] = v.default;
                 continue;
@@ -496,6 +496,11 @@ class ValidationUtils {
                 return fieldSchema.default;
             }
 
+            if (typeof configValue !== "string") {
+                this.logger.warn(`${name}.${key} is not a valid enum string. Using default value.`);
+                return fieldSchema.default;
+            }
+
             const validValues = rules.values.map(e => e.value.toLowerCase());
 
             //remove caps
diff --git a/src/measurements/Measurement.js b/src/measurements/Measurement.js
index 0848657..da35e51 100644
--- a/src/measurements/Measurement.js
+++ b/src/measurements/Measurement.js
@@ -69,8 +69,10 @@ class Measurement {
   }
 
   getLaggedValue(lag){
-    if(this.values.length <= lag) return null;
-    return this.values[this.values.length - lag];
+    if (lag < 0) throw new Error('lag must be >= 0');
+    const index = this.values.length - 1 - lag;
+    if (index < 0) return null;
+    return this.values[index];
   }
 
   getLaggedSample(lag){
@@ -178,7 +180,7 @@ class Measurement {
     
     try {
       const convertedValues = this.values.map(value => 
-        convertModule.convert(value).from(this.unit).to(targetUnit)
+        convertModule(value).from(this.unit).to(targetUnit)
       );
       
       const newMeasurement = new Measurement(
diff --git a/src/measurements/MeasurementContainer.js b/src/measurements/MeasurementContainer.js
index d67786b..21412d0 100644
--- a/src/measurements/MeasurementContainer.js
+++ b/src/measurements/MeasurementContainer.js
@@ -332,7 +332,7 @@ class MeasurementContainer {
     // Convert if needed
     if (measurement.unit && requestedUnit !== measurement.unit) {
       try {
-        const convertedValue = convertModule(value).from(measurement.unit).to(requestedUnit);
+        const convertedValue = convertModule(sample.value).from(measurement.unit).to(requestedUnit);
         //replace old value in sample and return obj
         sample.value = convertedValue ;
         sample.unit = requestedUnit;
@@ -364,7 +364,7 @@ class MeasurementContainer {
     // Convert if needed
     if (measurement.unit && requestedUnit !== measurement.unit) {
       try {
-        const convertedValue = convertModule(value).from(measurement.unit).to(requestedUnit);
+        const convertedValue = convertModule(sample.value).from(measurement.unit).to(requestedUnit);
         //replace old value in sample and return obj
         sample.value = convertedValue ;
         sample.unit = requestedUnit;
@@ -619,16 +619,16 @@ class MeasurementContainer {
   }
 
   _convertPositionNum2Str(positionValue) {
-    switch (positionValue) {
-    case 0:
+    if (positionValue === 0) {
       return "atEquipment";
-    case (positionValue < 0):
-      return "upstream";
-    case (positionValue > 0):
-      return "downstream";
-    default:
-      console.log(`Invalid position provided: ${positionValue}`);
     }
+    if (positionValue < 0) {
+      return "upstream";
+    }
+    if (positionValue > 0) {
+      return "downstream";
+    }
+    console.log(`Invalid position provided: ${positionValue}`);
   }
 
 }
diff --git a/src/menu/index.js b/src/menu/index.js
index 7fb8ee2..a216548 100644
--- a/src/menu/index.js
+++ b/src/menu/index.js
@@ -36,7 +36,21 @@ class MenuManager {
 
         try {
             const config = this.configManager.getConfig(nodeName);
-            return config?.functionality?.softwareType || nodeName;
+            const softwareType = config?.functionality?.softwareType;
+
+            if (typeof softwareType === 'string' && softwareType.trim()) {
+                return softwareType;
+            }
+            if (
+                softwareType &&
+                typeof softwareType === 'object' &&
+                typeof softwareType.default === 'string' &&
+                softwareType.default.trim()
+            ) {
+                return softwareType.default;
+            }
+
+            return nodeName;
         } catch (error) {
             console.warn(`Unable to determine softwareType for ${nodeName}: ${error.message}`);
             return nodeName;
diff --git a/test/00-barrel-contract.test.js b/test/00-barrel-contract.test.js
new file mode 100644
index 0000000..ea7008e
--- /dev/null
+++ b/test/00-barrel-contract.test.js
@@ -0,0 +1,42 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const barrel = require('../index.js');
+
+test('barrel exports expected public members', () => {
+  const expected = [
+    'predict',
+    'interpolation',
+    'configManager',
+    'assetApiConfig',
+    'outputUtils',
+    'configUtils',
+    'logger',
+    'validation',
+    'assertions',
+    'MeasurementContainer',
+    'nrmse',
+    'state',
+    'coolprop',
+    'convert',
+    'MenuManager',
+    'childRegistrationUtils',
+    'loadCurve',
+    'loadModel',
+    'gravity',
+  ];
+
+  for (const key of expected) {
+    assert.ok(key in barrel, `missing export: ${key}`);
+  }
+});
+
+test('barrel types are callable where expected', () => {
+  assert.equal(typeof barrel.logger, 'function');
+  assert.equal(typeof barrel.validation, 'function');
+  assert.equal(typeof barrel.configUtils, 'function');
+  assert.equal(typeof barrel.outputUtils, 'function');
+  assert.equal(typeof barrel.MeasurementContainer, 'function');
+  assert.equal(typeof barrel.convert, 'function');
+  assert.equal(typeof barrel.gravity.getStandardGravity, 'function');
+});
diff --git a/test/assertions.test.js b/test/assertions.test.js
new file mode 100644
index 0000000..48ce4c0
--- /dev/null
+++ b/test/assertions.test.js
@@ -0,0 +1,14 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const Assertions = require('../src/helper/assertionUtils.js');
+
+test('assertNoNaN does not throw for valid nested arrays', () => {
+  const assertions = new Assertions();
+  assert.doesNotThrow(() => assertions.assertNoNaN([1, [2, 3, [4]]]));
+});
+
+test('assertNoNaN throws when NaN exists in nested arrays', () => {
+  const assertions = new Assertions();
+  assert.throws(() => assertions.assertNoNaN([1, [2, NaN]]), /NaN detected/);
+});
diff --git a/test/child-registration-utils.test.js b/test/child-registration-utils.test.js
new file mode 100644
index 0000000..ca2ea75
--- /dev/null
+++ b/test/child-registration-utils.test.js
@@ -0,0 +1,55 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const ChildRegistrationUtils = require('../src/helper/childRegistrationUtils.js');
+
+function makeMainClass() {
+  return {
+    logger: {
+      debug() {},
+      info() {},
+      warn() {},
+      error() {},
+    },
+    child: {},
+    registerChildCalls: [],
+    registerChild(child, softwareType) {
+      this.registerChildCalls.push({ child, softwareType });
+    },
+  };
+}
+
+test('registerChild wires parent, measurement context, and storage', async () => {
+  const mainClass = makeMainClass();
+  const utils = new ChildRegistrationUtils(mainClass);
+
+  const measurementContext = {
+    childId: null,
+    childName: null,
+    parentRef: null,
+    setChildId(v) { this.childId = v; },
+    setChildName(v) { this.childName = v; },
+    setParentRef(v) { this.parentRef = v; },
+  };
+
+  const child = {
+    config: {
+      functionality: { softwareType: 'measurement' },
+      general: { name: 'PT1', id: 'child-1' },
+      asset: { category: 'sensor' },
+    },
+    measurements: measurementContext,
+  };
+
+  await utils.registerChild(child, 'upstream');
+
+  assert.deepEqual(child.parent, [mainClass]);
+  assert.equal(child.positionVsParent, 'upstream');
+  assert.equal(measurementContext.childId, 'child-1');
+  assert.equal(measurementContext.childName, 'PT1');
+  assert.equal(measurementContext.parentRef, mainClass);
+
+  assert.equal(mainClass.child.measurement.sensor.length, 1);
+  assert.equal(utils.getChildById('child-1'), child);
+  assert.equal(mainClass.registerChildCalls.length, 1);
+});
diff --git a/test/config-manager.test.js b/test/config-manager.test.js
new file mode 100644
index 0000000..e7147a1
--- /dev/null
+++ b/test/config-manager.test.js
@@ -0,0 +1,33 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const ConfigManager = require('../src/configs/index.js');
+
+test('can read known config and report existence', () => {
+  const manager = new ConfigManager('.');
+  assert.equal(manager.hasConfig('measurement'), true);
+
+  const config = manager.getConfig('measurement');
+  assert.ok(config.functionality);
+  assert.ok(config.functionality.softwareType);
+});
+
+test('getAvailableConfigs includes known names', () => {
+  const manager = new ConfigManager('.');
+  const configs = manager.getAvailableConfigs();
+  assert.ok(configs.includes('measurement'));
+  assert.ok(configs.includes('rotatingMachine'));
+});
+
+test('createEndpoint creates executable JS payload shell', () => {
+  const manager = new ConfigManager('.');
+  const script = manager.createEndpoint('measurement');
+
+  assert.match(script, /window\.EVOLV\.nodes\.measurement/);
+  assert.match(script, /config loaded and endpoint created/);
+});
+
+test('getConfig throws on missing config', () => {
+  const manager = new ConfigManager('.');
+  assert.throws(() => manager.getConfig('definitely-not-real'), /Failed to load config/);
+});
diff --git a/test/config-utils.test.js b/test/config-utils.test.js
new file mode 100644
index 0000000..cee7b79
--- /dev/null
+++ b/test/config-utils.test.js
@@ -0,0 +1,51 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const ConfigUtils = require('../src/helper/configUtils.js');
+
+const defaultConfig = {
+  functionality: {
+    softwareType: {
+      default: 'measurement',
+      rules: { type: 'string' },
+    },
+  },
+  general: {
+    logging: {
+      enabled: { default: true, rules: { type: 'boolean' } },
+      logLevel: {
+        default: 'info',
+        rules: {
+          type: 'enum',
+          values: [{ value: 'debug' }, { value: 'info' }, { value: 'warn' }, { value: 'error' }],
+        },
+      },
+    },
+    name: { default: 'default-name', rules: { type: 'string' } },
+  },
+  scaling: {
+    absMin: { default: 0, rules: { type: 'number' } },
+    absMax: { default: 100, rules: { type: 'number' } },
+  },
+};
+
+test('initConfig applies defaults', () => {
+  const cfg = new ConfigUtils(defaultConfig, false, 'error');
+  const result = cfg.initConfig({});
+  assert.equal(result.general.name, 'default-name');
+  assert.equal(result.scaling.absMax, 100);
+});
+
+test('updateConfig merges nested overrides and revalidates', () => {
+  const cfg = new ConfigUtils(defaultConfig, false, 'error');
+  const base = cfg.initConfig({ general: { name: 'sensor-a' } });
+  const updated = cfg.updateConfig(base, { scaling: { absMax: 150 } });
+
+  assert.equal(updated.general.name, 'sensor-a');
+  assert.equal(updated.scaling.absMax, 150);
+});
+
+test('constructor respects explicit logger disabled flag', () => {
+  const cfg = new ConfigUtils(defaultConfig, false, 'error');
+  assert.equal(cfg.logger.logging, false);
+});
diff --git a/test/gravity.test.js b/test/gravity.test.js
new file mode 100644
index 0000000..f954a72
--- /dev/null
+++ b/test/gravity.test.js
@@ -0,0 +1,21 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const gravity = require('../src/helper/gravity.js');
+
+test('standard gravity constant is available', () => {
+  assert.ok(Math.abs(gravity.getStandardGravity() - 9.80665) < 1e-9);
+});
+
+test('local gravity decreases with elevation', () => {
+  const seaLevel = gravity.getLocalGravity(45, 0);
+  const high = gravity.getLocalGravity(45, 1000);
+  assert.ok(high < seaLevel);
+});
+
+test('pressureHead and weightForce use local gravity', () => {
+  const dp = gravity.pressureHead(1000, 5, 45, 0);
+  const force = gravity.weightForce(2, 45, 0);
+  assert.ok(dp > 0);
+  assert.ok(force > 0);
+});
diff --git a/test/helpers.js b/test/helpers.js
new file mode 100644
index 0000000..870df5e
--- /dev/null
+++ b/test/helpers.js
@@ -0,0 +1,24 @@
+const path = require('node:path');
+
+function makeLogger() {
+  return {
+    debug() {},
+    info() {},
+    warn() {},
+    error() {},
+  };
+}
+
+function near(actual, expected, epsilon = 1e-6) {
+  return Math.abs(actual - expected) <= epsilon;
+}
+
+function fixturePath(...segments) {
+  return path.join(__dirname, ...segments);
+}
+
+module.exports = {
+  makeLogger,
+  near,
+  fixturePath,
+};
diff --git a/test/logger.test.js b/test/logger.test.js
new file mode 100644
index 0000000..c3a3f8c
--- /dev/null
+++ b/test/logger.test.js
@@ -0,0 +1,65 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const Logger = require('../src/helper/logger.js');
+
+function withPatchedConsole(fn) {
+  const original = {
+    debug: console.debug,
+    info: console.info,
+    warn: console.warn,
+    error: console.error,
+  };
+
+  const calls = [];
+  console.debug = (...args) => calls.push(['debug', ...args]);
+  console.info = (...args) => calls.push(['info', ...args]);
+  console.warn = (...args) => calls.push(['warn', ...args]);
+  console.error = (...args) => calls.push(['error', ...args]);
+
+  try {
+    fn(calls);
+  } finally {
+    console.debug = original.debug;
+    console.info = original.info;
+    console.warn = original.warn;
+    console.error = original.error;
+  }
+}
+
+test('respects log level threshold', () => {
+  withPatchedConsole((calls) => {
+    const logger = new Logger(true, 'warn', 'T');
+    logger.debug('a');
+    logger.info('b');
+    logger.warn('c');
+    logger.error('d');
+
+    const levels = calls.map((c) => c[0]);
+    assert.deepEqual(levels, ['warn', 'error']);
+  });
+});
+
+test('toggleLogging disables output', () => {
+  withPatchedConsole((calls) => {
+    const logger = new Logger(true, 'debug', 'T');
+    logger.toggleLogging();
+    logger.debug('x');
+    logger.error('y');
+    assert.equal(calls.length, 0);
+  });
+});
+
+test('setLogLevel updates to valid level', () => {
+  const logger = new Logger(true, 'debug', 'T');
+  logger.setLogLevel('error');
+  assert.equal(logger.logLevel, 'error');
+});
+
+test('setLogLevel with invalid value should not throw', () => {
+  withPatchedConsole(() => {
+    const logger = new Logger(true, 'debug', 'T');
+    assert.doesNotThrow(() => logger.setLogLevel('invalid-level'));
+    assert.equal(logger.logLevel, 'debug');
+  });
+});
diff --git a/test/measurement-builder.test.js b/test/measurement-builder.test.js
new file mode 100644
index 0000000..0ae553a
--- /dev/null
+++ b/test/measurement-builder.test.js
@@ -0,0 +1,29 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const MeasurementBuilder = require('../src/measurements/MeasurementBuilder.js');
+
+test('builder requires mandatory fields', () => {
+  assert.throws(() => new MeasurementBuilder().build(), /Measurement type is required/);
+  assert.throws(() => new MeasurementBuilder().setType('flow').build(), /Measurement variant is required/);
+  assert.throws(
+    () => new MeasurementBuilder().setType('flow').setVariant('measured').build(),
+    /Measurement position is required/
+  );
+});
+
+test('builder creates measurement with provided config', () => {
+  const measurement = new MeasurementBuilder()
+    .setType('flow')
+    .setVariant('measured')
+    .setPosition('upstream')
+    .setWindowSize(25)
+    .setDistance(3.2)
+    .build();
+
+  assert.equal(measurement.type, 'flow');
+  assert.equal(measurement.variant, 'measured');
+  assert.equal(measurement.position, 'upstream');
+  assert.equal(measurement.windowSize, 25);
+  assert.equal(measurement.distance, 3.2);
+});
diff --git a/test/measurement-container-core.test.js b/test/measurement-container-core.test.js
new file mode 100644
index 0000000..2a4554a
--- /dev/null
+++ b/test/measurement-container-core.test.js
@@ -0,0 +1,61 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const MeasurementContainer = require('../src/measurements/MeasurementContainer.js');
+
+function makeContainer() {
+  return new MeasurementContainer({
+    windowSize: 10,
+    defaultUnits: {
+      flow: 'm3/h',
+      pressure: 'mbar',
+    },
+  });
+}
+
+test('stores and retrieves measurements via chain API', () => {
+  const c = makeContainer();
+  c.type('flow').variant('measured').position('upstream').value(100, 1, 'm3/h');
+
+  assert.equal(c.type('flow').variant('measured').position('upstream').getCurrentValue(), 100);
+  assert.equal(c.type('flow').variant('measured').position('upstream').exists(), true);
+});
+
+test('distance(null) auto-derives from position mapping', () => {
+  const c = makeContainer();
+  c.type('pressure').variant('measured').position('upstream').distance(null).value(5, 1, 'mbar');
+
+  const m = c.type('pressure').variant('measured').position('upstream').get();
+  assert.equal(m.distance, Number.POSITIVE_INFINITY);
+});
+
+test('getLaggedSample with requested unit converts sample value', () => {
+  const c = makeContainer();
+  c.type('flow').variant('measured').position('upstream').value(3.6, 1, 'm3/h');
+  c.type('flow').variant('measured').position('upstream').value(7.2, 2, 'm3/h');
+
+  const previous = c.type('flow').variant('measured').position('upstream').getLaggedSample(1, 'm3/s');
+  assert.ok(previous);
+  assert.equal(previous.unit, 'm3/s');
+  assert.ok(Math.abs(previous.value - 0.001) < 1e-8);
+});
+
+test('difference computes current and average delta between positions', () => {
+  const c = makeContainer();
+  c.type('pressure').variant('measured').position('downstream').value(120, 1, 'mbar');
+  c.type('pressure').variant('measured').position('downstream').value(130, 2, 'mbar');
+  c.type('pressure').variant('measured').position('upstream').value(100, 1, 'mbar');
+  c.type('pressure').variant('measured').position('upstream').value(110, 2, 'mbar');
+
+  const diff = c.type('pressure').variant('measured').difference();
+  assert.equal(diff.value, 20);
+  assert.equal(diff.avgDiff, 20);
+  assert.equal(diff.unit, 'mbar');
+});
+
+test('_convertPositionNum2Str maps signs to labels', () => {
+  const c = makeContainer();
+  assert.equal(c._convertPositionNum2Str(0), 'atEquipment');
+  assert.equal(c._convertPositionNum2Str(1), 'downstream');
+  assert.equal(c._convertPositionNum2Str(-1), 'upstream');
+});
diff --git a/test/measurement.test.js b/test/measurement.test.js
new file mode 100644
index 0000000..a456642
--- /dev/null
+++ b/test/measurement.test.js
@@ -0,0 +1,49 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const Measurement = require('../src/measurements/Measurement.js');
+const { near } = require('./helpers.js');
+
+test('maintains rolling window and exposes stats', () => {
+  const m = new Measurement('flow', 'measured', 'upstream', 3);
+  m.setValue(10, 1).setValue(20, 2).setValue(30, 3).setValue(40, 4);
+
+  assert.deepEqual(m.getAllValues().values, [20, 30, 40]);
+  assert.deepEqual(m.getAllValues().timestamps, [2, 3, 4]);
+  assert.equal(m.getCurrentValue(), 40);
+  assert.equal(m.getAverage(), 30);
+  assert.equal(m.getMin(), 20);
+  assert.equal(m.getMax(), 40);
+});
+
+test('lag semantics: lag=1 is previous sample', () => {
+  const m = new Measurement('flow', 'measured', 'upstream', 5);
+  m.setValue(10, 100).setValue(20, 200).setValue(30, 300);
+
+  assert.equal(m.getLaggedSample(0).value, 30);
+  assert.equal(m.getLaggedSample(1).value, 20);
+  assert.equal(m.getLaggedValue(1), 20);
+});
+
+test('convertTo converts values to target unit', () => {
+  const m = new Measurement('flow', 'measured', 'upstream', 5);
+  m.setUnit('m3/h');
+  m.setValue(3.6, 1);
+
+  const converted = m.convertTo('m3/s');
+  assert.ok(near(converted.getCurrentValue(), 0.001, 1e-8));
+  assert.equal(converted.unit, 'm3/s');
+  assert.equal(converted.getLatestTimestamp(), 1);
+});
+
+test('createDifference aligns timestamps and subtracts downstream from upstream', () => {
+  const up = new Measurement('pressure', 'measured', 'upstream', 10).setUnit('mbar');
+  const down = new Measurement('pressure', 'measured', 'downstream', 10).setUnit('mbar');
+
+  up.setValue(120, 1).setValue(140, 2);
+  down.setValue(100, 2).setValue(95, 3);
+
+  const diff = Measurement.createDifference(up, down);
+  assert.deepEqual(diff.getAllValues().timestamps, [2]);
+  assert.deepEqual(diff.getAllValues().values, [40]);
+});
diff --git a/test/menu-manager.test.js b/test/menu-manager.test.js
new file mode 100644
index 0000000..e80e9d7
--- /dev/null
+++ b/test/menu-manager.test.js
@@ -0,0 +1,20 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const MenuManager = require('../src/menu/index.js');
+
+test('createEndpoint returns script including initEditor and menuData', () => {
+  const manager = new MenuManager();
+  const script = manager.createEndpoint('measurement', ['asset', 'logger', 'position']);
+
+  assert.match(script, /window\.EVOLV\.nodes\.measurement\.initEditor/);
+  assert.match(script, /window\.EVOLV\.nodes\.measurement\.menuData/);
+});
+
+test('_getSoftwareType resolves to string identifier', () => {
+  const manager = new MenuManager();
+  const softwareType = manager._getSoftwareType('measurement');
+
+  assert.equal(typeof softwareType, 'string');
+  assert.equal(softwareType, 'measurement');
+});
diff --git a/test/nrmse.test.js b/test/nrmse.test.js
new file mode 100644
index 0000000..a52f053
--- /dev/null
+++ b/test/nrmse.test.js
@@ -0,0 +1,37 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const ErrorMetrics = require('../src/nrmse/errorMetrics.js');
+const { makeLogger } = require('./helpers.js');
+
+test('MSE and RMSE calculations are correct', () => {
+  const m = new ErrorMetrics({}, makeLogger());
+  const predicted = [1, 2, 3];
+  const measured = [1, 3, 5];
+
+  assert.ok(Math.abs(m.meanSquaredError(predicted, measured) - 5 / 3) < 1e-9);
+  assert.ok(Math.abs(m.rootMeanSquaredError(predicted, measured) - Math.sqrt(5 / 3)) < 1e-9);
+});
+
+test('normalizeUsingRealtime throws when range is zero', () => {
+  const m = new ErrorMetrics({}, makeLogger());
+  assert.throws(() => m.normalizeUsingRealtime([1, 1, 1], [1, 1, 1]), /Invalid process range/);
+});
+
+test('longTermNRMSD returns 0 before 100 samples and value after', () => {
+  const m = new ErrorMetrics({}, makeLogger());
+  for (let i = 0; i < 99; i++) {
+    assert.equal(m.longTermNRMSD(0.1), 0);
+  }
+  assert.notEqual(m.longTermNRMSD(0.2), 0);
+});
+
+test('assessDrift returns expected result envelope', () => {
+  const m = new ErrorMetrics({}, makeLogger());
+  const out = m.assessDrift([100, 101, 102], [99, 100, 103], 90, 110);
+
+  assert.equal(typeof out.nrmse, 'number');
+  assert.equal(typeof out.longTermNRMSD, 'number');
+  assert.ok('immediateLevel' in out);
+  assert.ok('longTermLevel' in out);
+});
diff --git a/test/output-utils.test.js b/test/output-utils.test.js
new file mode 100644
index 0000000..d901b2d
--- /dev/null
+++ b/test/output-utils.test.js
@@ -0,0 +1,42 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const OutputUtils = require('../src/helper/outputUtils.js');
+
+const config = {
+  functionality: { softwareType: 'measurement', role: 'sensor' },
+  general: { id: 'abc', unit: 'mbar' },
+  asset: {
+    uuid: 'u1',
+    tagcode: 't1',
+    geoLocation: { lat: 51.6, lon: 4.7 },
+    category: 'measurement',
+    type: 'pressure',
+    model: 'M1',
+  },
+};
+
+test('process format emits message with changed fields only', () => {
+  const out = new OutputUtils();
+
+  const first = out.formatMsg({ a: 1, b: 2 }, config, 'process');
+  assert.equal(first.topic, 'measurement_abc');
+  assert.deepEqual(first.payload, { a: 1, b: 2 });
+
+  const second = out.formatMsg({ a: 1, b: 2 }, config, 'process');
+  assert.equal(second, undefined);
+
+  const third = out.formatMsg({ a: 1, b: 3, c: { x: 1 } }, config, 'process');
+  assert.deepEqual(third.payload, { b: 3, c: JSON.stringify({ x: 1 }) });
+});
+
+test('influx format flattens tags and stringifies tag values', () => {
+  const out = new OutputUtils();
+  const msg = out.formatMsg({ value: 10 }, config, 'influxdb');
+
+  assert.equal(msg.topic, 'measurement_abc');
+  assert.equal(msg.payload.measurement, 'measurement_abc');
+  assert.equal(msg.payload.tags.geoLocation_lat, '51.6');
+  assert.equal(msg.payload.tags.geoLocation_lon, '4.7');
+  assert.ok(msg.payload.timestamp instanceof Date);
+});
diff --git a/test/validation-utils.test.js b/test/validation-utils.test.js
new file mode 100644
index 0000000..7a5c71e
--- /dev/null
+++ b/test/validation-utils.test.js
@@ -0,0 +1,62 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const ValidationUtils = require('../src/helper/validationUtils.js');
+
+const schema = {
+  functionality: {
+    softwareType: {
+      default: 'measurement',
+      rules: { type: 'string' },
+    },
+  },
+  enabled: {
+    default: true,
+    rules: { type: 'boolean' },
+  },
+  mode: {
+    default: 'auto',
+    rules: {
+      type: 'enum',
+      values: [{ value: 'auto' }, { value: 'manual' }],
+    },
+  },
+  name: {
+    default: 'sensor',
+    rules: { type: 'string' },
+  },
+};
+
+test('validateSchema applies defaults and type coercion where supported', () => {
+  const validation = new ValidationUtils(false, 'error');
+  const result = validation.validateSchema({ enabled: 'true', name: 'SENSOR' }, schema, 'test');
+
+  assert.equal(result.enabled, true);
+  assert.equal(result.name, 'sensor');
+  assert.equal(result.mode, 'auto');
+  assert.equal(result.functionality.softwareType, 'measurement');
+});
+
+test('enum with non-string value falls back to default', () => {
+  const validation = new ValidationUtils(false, 'error');
+  const result = validation.validateSchema({ mode: 123 }, schema, 'test');
+  assert.equal(result.mode, 'auto');
+});
+
+test('curve validation falls back to default for invalid dimension structure', () => {
+  const validation = new ValidationUtils(false, 'error');
+  const defaultCurve = { 1: { x: [1, 2], y: [10, 20] } };
+  const invalid = { 1: { x: [2, 1], y: [20, 10] } };
+  const curve = validation.validateCurve(invalid, defaultCurve);
+  assert.deepEqual(curve, defaultCurve);
+});
+
+test('removeUnwantedKeys handles primitive values without throwing', () => {
+  const validation = new ValidationUtils(false, 'error');
+  const input = {
+    a: { default: 1, rules: { type: 'number' } },
+    b: 2,
+    c: 'x',
+  };
+  assert.doesNotThrow(() => validation.removeUnwantedKeys(input));
+});