Auto: focas-f4b — cnc_wrmacro + cnc_wrparam writes

Closes #269

scripts/e2e/test-focas.ps1

@@ -28,12 +28,25 @@
   NodeId at which the server publishes the Address.
 
 .PARAMETER Write
-  Issue #268 / plan PR F4-a — opts the script into the post-F4-a write
-  stages. F4-a ships the write infrastructure (driver-level Writes.Enabled
-  flag + per-tag Writable opt-in) without any actual wire writes; F4-b/c
-  populate this stage with real macro / parameter / PMC write coverage.
-  Until then the switch is a no-op marker so the e2e harness records that
-  the write surface was deliberately exercised (or skipped).
+  Issue #268 (F4-a) + #269 (F4-b) — opts the script into write stages.
+  Without -Write the script runs read-only probe / loopback / bridge
+  coverage. With -Write the script additionally exercises the F4-b
+  cnc_wrparam + cnc_wrmacro round-trip stages against the configured
+  -ParamAddress / -MacroAddress (default safe values). The wire writes
+  fire only when FOCAS_TRUST_WIRE=1 (already gated above) AND the
+  operator explicitly requests the write path.
+
+.PARAMETER ParamAddress
+  Parameter address for the F4-b write stage (default PARAM:1815).
+  Only used when -Write is supplied. Pick a parameter that's safe to
+  scribble on for your CNC setup — the default is benign for a stock
+  Fanuc 30i but every site differs.
+
+.PARAMETER MacroAddress
+  Macro variable for the F4-b write stage (default MACRO:500). Macro
+  writes are the lowest-risk write surface (no parameter-write switch
+  needed, no MDI mode required) so this stage runs whenever -Write is
+  supplied.
 #>
 
 param(
@@ -42,7 +55,9 @@ param(
     [string]$Address = "R100",
     [string]$OpcUaUrl = "opc.tcp://localhost:4840",
     [Parameter(Mandatory)] [string]$BridgeNodeId,
-    [switch]$Write
+    [switch]$Write,
+    [string]$ParamAddress = "PARAM:1815",
+    [string]$MacroAddress = "MACRO:500"
 )
 
 $ErrorActionPreference = "Stop"
@@ -102,11 +117,35 @@ $results += Test-SubscribeSeesChange `
     -ExpectedValue "$subValue"
 
 if ($Write) {
-    # F4-a no-op stage. Real per-kind write coverage lands in F4-b/c which extend the wire
-    # client past the BadNotSupported short-circuit + populate this branch with
-    # macro / parameter / PMC write assertions. Logged here so the harness records that the
-    # operator deliberately requested the write path.
-    Write-Host "[skip] -Write requested; F4-a ships infrastructure only — wire-write stages land in F4-b/c (issue #268)."
+    # F4-b — macro + parameter round-trip writes. Both stages use the same
+    # write-then-read shape the existing PMC stages use; the per-tag value
+    # comes back through Test-DriverLoopback's read step.
+    #
+    # Macro writes run unconditionally when -Write is supplied — no MDI / no
+    # parameter-write switch dependency, lowest-risk write surface on a CNC.
+    $macroValue = Get-Random -Minimum 100 -Maximum 9999
+    $results += Test-DriverLoopback `
+        -Cli $focasCli `
+        -WriteArgs (@("write") + $commonFocas + @("-a", $MacroAddress, "-t", "Int32", "-v", $macroValue)) `
+        -ReadArgs  (@("read")  + $commonFocas + @("-a", $MacroAddress, "-t", "Int32")) `
+        -ExpectedValue "$macroValue"
+
+    # Parameter writes only fire when the operator double-opts in via
+    # FOCAS_PARAM_WRITE=1. The CNC must be in MDI mode + parameter-write
+    # switch enabled or every write returns EW_PASSWD (BadUserAccessDenied);
+    # without an opt-in the script won't even attempt the write. F4-d will
+    # land an OPC UA-side unlock workflow that lets this stage run without
+    # the pendant.
+    if ($env:FOCAS_PARAM_WRITE -eq "1" -or $env:FOCAS_PARAM_WRITE -eq "true") {
+        $paramValue = Get-Random -Minimum 100 -Maximum 9999
+        $results += Test-DriverLoopback `
+            -Cli $focasCli `
+            -WriteArgs (@("write") + $commonFocas + @("-a", $ParamAddress, "-t", "Int32", "-v", $paramValue)) `
+            -ReadArgs  (@("read")  + $commonFocas + @("-a", $ParamAddress, "-t", "Int32")) `
+            -ExpectedValue "$paramValue"
+    } else {
+        Write-Host "[skip] FOCAS_PARAM_WRITE not set — parameter-write stage requires the CNC to be in MDI mode + parameter-write switch enabled (see docs/v2/focas-deployment.md 'Write safety')."
+    }
 }
 
 Write-Summary -Title "FOCAS e2e" -Results $results