Address space overview

All ten classic servers expose the same application address space — around 200 custom nodes rooted under one folder, plus the framework nodes that every UA-.NETStandard server provides in ns=0.

Namespaces

TestNodeManager registers exactly three URIs at construction time:

http://opcfoundation.org/UA/ is always present in any UA server as ns=0. The actual numeric index for each of the custom URIs above is assigned by the SDK at startup and should be read out of Server.NamespaceArray rather than hardcoded — the indices above are the typical allocations and have been stable across builds, but they are not pinned.

Almost everything tests reach for is in ns=1. Extension-object type definitions and their encoding nodes are in urn:opcua:test-server:custom-types (typically ns=3); see Structures and extension objects for the encoding NodeIds.

NodeId format

NodeIds in ns=1 use string identifiers wherever stable navigation matters:

ns=1;s=TestServer/DataTypes/Scalar/BooleanValue
ns=1;s=TestServer/Methods/Add
ns=1;s=TestServer/Dynamic/Counter

This is by convention — the suite generates string NodeIds for every node it creates, so tests can address nodes by stable name across server restarts.

Numeric NodeIds are used by some auto-generated nodes (the standard ones in ns=0). For ns=1 test nodes, prefer string NodeIds.

ApplicationUri

urn:opcua:testserver:nodes

Same for every classic server — they all advertise the same application URI. This is convenient (one trust entry) but means "distinguishing servers by URI" doesn't work — distinguish by endpoint URL or by port instead.

Root structure

Objects (ns=0;i=85)
└── TestServer (ns=1;s=TestServer)
    ├── DataTypes          # Scalars, arrays, matrices, analog
    ├── Methods            # 12 callable methods
    ├── Dynamic            # 13 time-varying variables
    ├── Events             # Single emitter object, three periodic BaseEventState timers
    ├── Alarms             # 3 alarms + 2 source variables
    ├── Historical         # 4 historized variables
    ├── Structures         # Nested objects, deep nesting
    ├── ExtensionObjects   # PointValue, RangeValue
    ├── AccessControl      # 50 access-mode test variables
    └── SecurityKeyService # Only on opcua-sks

Each top-level folder maps to one builder class in src/TestServer/AddressSpace/. They're independent — disabling one (via OPCUA_ENABLE_* env vars) doesn't affect the others.

Views

Views (ns=0;i=87)
├── OperatorView      → Dynamic, Methods, Alarms
├── EngineeringView   → Everything (TestServer root)
├── HistoricalView    → Historical
└── DataView          → DataTypes, Structures, ExtensionObjects

Views are filtered perspectives of the address space — see Views.

Folder-level browse

A single browse from TestServer returns the 9 (or 10 on SKS) top-level folders:

Node-count summary

Plus framework nodes (Server, Aliases, Namespaces) in ns=0 that every OPC UA server has.

Feature toggles

Each section is opt-out via OPCUA_ENABLE_* env vars:

The 10 classic servers all run with the full set on. A leaner fork might disable several.

Where to read next

• Browse paths and access levels — navigation conventions and access-level legend.
• The per-feature pages under Data features and Runtime features.