AngularJS; error when registering a controller - angularjs

Question

I'm not too familiar with Angular; I'm trying to use a controller and keep getting this error:
Error: [$controller:ctrlreg] The controller with the name 'MyControllerTest' is not registered.
This is what I put in the html file:
<script type="text/javascript">
var app = angular.module('myAppTest', []);
app.controller('MyControllerTest', function($scope) {
$scope.message = 'Test Message';
});
</script>
<div ng-app="myAppTest">
<div ng-controller="MyControllerTest">
{{message}}
</div>
</div>
I don't have full access to the entire system, I can either edit the html file or add code to the header tag. I tried moving the script section to the header tag with the same result. The site is using AngularJS v1.8.2 Any help would be appreciated!
The entire HTML snippet I'm trying to add this to is:
<style>
.product-details-page {
overflow: auto;
margin-left: 0 !important;
}
.product-details-page .modalContent {
height:auto;
}
#media only screen and (max-width : 986px) {
.product-details-page-image img, product-details-page-content {
width: 100%;
}
.product-details-page {
width:auto;
}
}
</style>
<div class="{{modalClass}} product-details-page" ng-cts-product-page-view="PageView_ProductDetails IncludeOnPage_ProductDetails">
<div class="modal-header product-details-page-header">
<div class="close" ng-show="EnableCloseOrBack()">
<a ng-click='CloseDialog()' href="javascript:" ><span aria-hidden="true" class="icon-cross"></span></a>
</div>
<div class="back" ng-show="(data.IsScreenSizeLimited && data.ConfirmationButtonAction == 2)" ng-show="EnableCloseOrBack()">
<a ng-click="loadKitPage()" href="javascript:" ><span aria-hidden="true" class="icon-arrow-left2"></span></a>
</div>
<div>
<span ng-show="(product!=null && product!=undefined)">{{product._Name}}</span>
<span ng-hide="(product!=null && product!=undefined)">{{getLocalizedString("ProductDetails.ProductUnavailable")}}</span>
</div>
</div>
<div class="modalContent" ng-show="(product!=null && product!=undefined)" ng-style="setProductDetailsHeight(windowHeight)">
<div class="product-details-page-image">
<img ng-src="{{product._DetailImageKey}}" alt="" ng-show="product._DetailImageKey" />
<img src='Images/no-image.png' alt="" ng-hide="product._DetailImageKey" />
</div>
<div class="product-details-page-content">
<div ng-show="product._ShowInventory" class="product-details-inventory">
<span>{{getStringWithVariableData(getLocalizedString("Product.DetailedInventoryCount"),[product._InventoryRemainingDisplay])}}</span>
</div>
<div ng-show="product._ShowPreviewLink" class="product-preview-link">
<span class="label" ng-localize="Shared.Preview"></span>
</div>
<div class="product-details-page-sku">
<span>{{getLocalizedString('Webpart.ProductDisplayItemNo')}}</span><span> {{product._SKU}} </span>
</div>
<div class="product-details-page-description">
<span ng-bind-html-unsafe="product._Description"></span>
</div>
<!-- add product pricing -->
<div ng-show="product._SKU == 'PRO-XXX'">
<!-- gives controller registration error -->
<script type="text/javascript">
var app = angular.module('myAppTest', []);
app.controller('MyControllerTest', function($scope) {
$scope.message = 'Test Message';
});
</script>
<div ng-app = "myAppTest">
<div ng-controller="MyControllerTest">
{{message}}
</div>
</div>
<!-- gives controller registration error -->
<table width="100%" cellpadding="10" cellspacing="0" border="0" ng-show="ShowPricing" class="product-price-matrix">
<thead>
<th><span>Test Quantity</span></th>
<th><span>Test Quantity Pricing</span></th>
</thead>
<tbody>
<tr ng-repeat="price in product.PricingDetails_asArray[0].PricingDetail_asArray">
<td><span> {{price.QtyRange}} </span></td>
<td><span> {{price.FormattedPrice}} </span></td>
</tr>
</tbody>
</table>
</div>
<!-- add product pricing -->
<div class="product-details-page-description">
<span ng-bind-html-unsafe="product._LongDescription"></span>
</div>
<!-- Added for customer 9 for preview links -->
<div ng-show="product._ShowExternalBuyerPreviewLink" class="product-preview-link">
<span class="label" ng-localize="Customer9.ExternalBuyerPreviewMessage"></span>
</div>
<!-- Added for customer 9 for new product alerts -->
<div ng-show="product._ShowIsNew" class="product-details-page-description">
<span ng-localize="Customer9.IsNewBuyerAlert"></span>
</div>
<div class="product-details-page-uom" ng-show="(product._IsSoundToBegin)">
<span ng-show="EnablePricingByUnitOfMeasure && product._UnitsOfMeasure !=undefined && product._UnitsOfMeasure.length>0">{{getLocalizedString("Pricing.OrderUnit")}}:</span>
<span title="{{product._UnitsOfMeasure}}" ng-bind-html-unsafe="product._UnitsOfMeasure"></span>
</div>
<div class="product-details-page-price" ng-show="(EnableRRDCustomization && ShowPricingToBuyer && ShowUnitPrice)">
<span>{{product._UnitPrice}}</span>
</div>
<div class="product-details-page-turn-around" ng-show="product._ShowTurnaround">
<span>{{getLocalizedString('AdHocBottomProductDetail.ProductDetails.TurnAroundTime') + product._Turnaround}}</span>
</div>
<table width="100%" cellpadding="10" cellspacing="0" border="0" ng-show="ShowMatrix" class="product-price-matrix">
<tbody>
<tr>
<td></td>
<td class="product-preview-link"><a ng-click='ResetFiltersAndProductMatrix()' href="javascript:"><span class="label" ng-localize="ManageApprovalSetings.ResetFilters"></span></a></td>
</tr>
<tr ng-repeat="Attribute in Currentproductmatrix">
<td><span> {{Attribute._DisplayName}}:</span></td>
<td><select ng-options="AttributeValue._DisplayName for AttributeValue in Attribute.AttributeValue_asArray | filter : FilterProductMatrix(Attribute.AttributeValue_asArray)" ng-change='DispLayProductMatrix(Attribute.AttributeValue,Attribute)' ng-model="Attribute.AttributeValue"></select></td>
</tr>
<tr ng-show="ShowMatrix && SubAttributes.ShowSubAttribute && ShowSubAttribute(product)">
<td><span>{{SubAttributes.SubAttributeName}}</span></td>
<td>
<input required="required" title="{{SubAttributes.SubAttributeName}}" type="text" ng-validate="{{SubAttributes.Validation}}" id="subAttributeNameValue" maxlength="200" ng-model="SubAttributes.SubAttributeValue">
<span class='validator-hint' id='hintValidatorsubAttributeNameValue' style="display: none;"></span>
</td>
</tr>
</tbody>
</table>
<div ng-show="ShowMatrix" class="product-details-page-description" style="margin-top: 10px;">
<span>{{getLocalizedString('Mobile.OrderLineItem.ProductName')}}:</span><span> {{product.DisplayName}} </span>
</div>
<table style="border:none !important">
<tr ng-show="data.ShowDeliverablesControl(product)">
<td style="border:none !important">
<label ng-localize="Deliverables" style="padding-right: 5px">##Deliverables</label>
</td>
<td style="border:none !important">
<label ng-show="(data.ConfirmationButtonAction==2 && isProductDetailsOpenFromKitToSelect)" style="padding-right: 5px"> : {{SelectedBuyerDelivarable.label}}</label>
<select ng-hide="(data.ConfirmationButtonAction==2 && isProductDetailsOpenFromKitToSelect)" ng-model="SelectedBuyerDelivarable" ng-change="deliverableChange()" ng-options="SelectedBuyerDelivarable.label for SelectedBuyerDelivarable in BuyerDelivarable"></select>
</td>
</tr>
<tr ng-show="ShowQuantityControl(product)">
<td>
<label for="" ng-localize="CatalogItemDetailsControl.Qty">##Qty</label>
</td>
<td>
<ng-quantity-control quantity="product.Quantity" selectedquantity="product.selectedquantity" isdownloadonly="IsDownloadOnly" registervalidationcallback="RegisterChildValidationControlCallbackFunction(CallbackFuncPointer,UniqueRef)"
registerclearquantitycallback="RegisterClearQuantityCallbackFunction(CallbackFuncPointer,UniqueRef)" uniquereference="data.currentProduct._CatalogItemID" onselectedvaluechange="OnProductSelectedQuantityChanged(UniqueIdentifier, Quantity)" includezeroquantity="false"
inventoryremaining="{{product._InventoryRemaining}}" displayerrorsonhover="false" allowbuyertoeditmultiplequantity="product._AllowBuyerToEditQuantity" group="product"></ng-quantity-control>
</td>
</tr>
</table>
<div ng-show="product.ShowReferenceCodes">
<span class="section-header" style="display: block;" ng-localize="Shared.CheckOutRefCode">reference</span></span>
<select ng-model="product.RefrenceCode" style="width: 95%;" id="{{product._CatalogItemID}}ProductDetails" ng-validate="{{product.Validations}}" ng-change="setrefernce(product)"
ng-options="RefrenceCode._Description group by RefrenceCode.group for RefrenceCode in product.ReferenceCodes"></select>
</div>
<div class="product-error-message" ng-hide="product._IsSoundToBegin">
<span title="{{product._CantBeginReason}}">{{getCantBeginReasonMessage(product)}}</span>
</div>
<div class="product-error-message" ng-show="data.isEditingByApprover && product._ApproverEditAllowed != 'true'">
<span>{{product._CantEditReason}}</span>
</div>
<div id="productErrorContainer" class="validation-container" style="display: none;width:100%;margin-top: 10px;margin-bottom: 10px">
<div class="validation-header">
<span class="icon-warning-sign"></span><span class="validaiton-info" ng-localize="inputerror"></span>
</div>
</div>
<table width="100%" cellpadding="10" cellspacing="0" border="0" ng-show="ShowPricing" class="product-price-matrix">
<thead>
<th><span ng-localize="Shared.Quantity"></span></th>
<th><span ng-localize="Webpart.ProductDisplayQuantityPricing"></span></th>
</thead>
<tbody>
<tr ng-repeat="price in product.PricingDetails_asArray[0].PricingDetail_asArray">
<td><span> {{price.QtyRange}} </span></td>
<td><span> {{price.FormattedPrice}} </span></td>
</tr>
</tbody>
</table>
<div ng-show="product._TaxAuthorityUsed">
<small>{{product._TaxAuthorityUsed}}</small>
</div>
</div>
</div>
<div class="modal-footer">
<div class="product-details-page-actions" ng-show="ShowFooter">
<button ng-class="{true:'btn',false:'btn disabled'}[product._IsSoundToBegin=='true']" type='submit' ng-click="openProductDialog('/ProductCustomization',product,0)" ng-hide="IsInCartUpdateMode || IsReadOnlyPunchOutSession">
<span id="" class="ng-binding" ng-hide="product._ProductType=='10'">{{product._BuyNowButtonText}} </span>
<span id="" class="ng-binding" ng-show="product._ProductType=='10'">{{getLocalizedString('Saepio.Design')}} </span>
</button>
<button class="btn btn-secondary" type='submit' ng-click="returnToPrevious()" ng-hide="IsInCartUpdateMode || IsLevelTwoPunchOut" ng-localize="ShoppingCart.ContinueShopping">
##Continue Shopping
</button>
<button ng-class="{true:'btn',false:'btn disabled'}[(data.isEditingByApprover ? (product._ApproverEditAllowed == 'true') : 'true')]" type='submit' ng-click="openProductDialog('/ProductCustomization',product,0)" ng-localize="Shared.Update" ng-show="IsInCartUpdateMode && !IsLevelTwoPunchOut">
<span id="" class="ng-binding" ng-localize="Shared.Update"></span>
</button>
</div>
<div class="product-details-page-actions" ng-hide="ShowFooter">
<button class="btn btn-secondary" type='submit' ng-click="CloseDialog()" ng-localize="Shared.Close" ng-hide="IsLevelTwoPunchOut" >
<span id="" class="ng-binding" ng-localize="Shared.Cancel"></span>
</button>
</div>
</div>
</div>