Set timezone in the target system on read-only mode

timezone/src/modules/Timezone.rb

@@ -254,23 +254,22 @@ def Set(zone, really)
       # Do not update the timezone if it's forced and it was already set
       if (Mode.installation || Mode.update) && readonly && !@timezone.empty?
         log.info "Timezone is read-only and cannot be changed during installation"
-        return -1
+      else
+        # Set the new timezone internally
+        @timezone = zone
       end
 
       zmap = get_zonemap
 
-      # Set the new timezone internally
-      @timezone = zone
-
       sel = 0
       while Ops.less_than(sel, Builtins.size(zmap)) &&
-          !Builtins.haskey(Ops.get_map(zmap, [sel, "entries"], {}), zone)
+          !Builtins.haskey(Ops.get_map(zmap, [sel, "entries"], {}), @timezone)
         sel = Ops.add(sel, 1)
       end
 
       @name = Ops.add(
         Ops.add(Ops.get_string(zmap, [sel, "name"], ""), " / "),
-        Ops.get_string(zmap, [sel, "entries", zone], zone)
+        Ops.get_string(zmap, [sel, "entries", @timezone], @timezone)
       )
 
       # Adjust system to the new timezone.

timezone/test/Timezone_test.rb

@@ -87,7 +87,7 @@
       allow(Yast::FileUtils).to receive(:IsLink).with("/etc/localtime").and_return(false)
     end
 
-    it "returns the timezone index" do
+    it "returns the region number" do
       expect(subject.Set("Atlantic/Canary", false)).to eq(3)
     end
 
@@ -105,8 +105,8 @@
         allow(Yast::Mode).to receive(:installation).and_return(true)
       end
 
-      it "returns -1" do
-        expect(subject.Set("Atlantic/Canary", false)).to eq(-1)
+      it "returns the region number" do
+        expect(subject.Set("Atlantic/Canary", false)).to eq(10) # UTC
       end
 
       it "does not modify the timezone" do
@@ -118,7 +118,7 @@
     context "when timezone is read-only in a running system" do
       let(:readonly_timezone) { true }
 
-      it "returns the timezone index" do
+      it "returns the region number" do
         expect(subject.Set("Atlantic/Canary", false)).to eq(3)
       end