test(dotnet): source staged feature helper script

Author: sliekens

test/dotnet/dotnet_helpers.sh

@@ -1,49 +1,7 @@
 #!/bin/bash
 
-DOTNET_RELEASES_INDEX_URL="https://builds.dotnet.microsoft.com/dotnet/release-metadata/releases-index.json"
-
-# Prints the latest active dotnet version from the releases index.
-# Usage: fetch_latest_version [<target>]
-# With no target, resolves the latest SDK version.
-# With "sdk", resolves the latest SDK version explicitly.
-# With "dotnet" or "aspnetcore", resolves the latest runtime version.
-# Note: the upstream releases index only distinguishes SDK vs runtime for
-# latest resolution, so "dotnet" and "aspnetcore" currently resolve to the
-# same version.
-# Example: fetch_latest_version
-# Example: fetch_latest_version "sdk"
-# Example: fetch_latest_version "dotnet"
-# Example: fetch_latest_version "aspnetcore"
-fetch_latest_version() {
-    local target="$1"
-    local version_field=""
-    local releases_index=""
-
-    case "$target" in
-        ""|sdk)
-            version_field="latest-sdk"
-            ;;
-        dotnet|aspnetcore)
-            version_field="latest-runtime"
-            ;;
-        *)
-            echo "Unsupported target '$target'. Expected 'sdk', 'dotnet', or 'aspnetcore'." >&2
-            return 1
-            ;;
-    esac
-
-    releases_index="$(wget -qO- "$DOTNET_RELEASES_INDEX_URL")" || return $?
-
-    printf '%s\n' "$releases_index" \
-        | jq -er --arg version_field "$version_field" '
-            .["releases-index"]
-            | map(
-                select(."support-phase" == "active")
-                | .[$version_field]
-            )
-            | .[0]
-        '
-}
+# Include the same helper functions used by the install script
+source ".devcontainer/dotnet/scripts/dotnet-helpers.sh"
 
 # Asserts that the specified .NET SDK version is installed
 # Returns a non-zero exit code if the check fails