diff --git a/spec/lib/appsignal/transmitter_spec.rb b/spec/lib/appsignal/transmitter_spec.rb
index fc740d06..91067e52 100644
--- a/spec/lib/appsignal/transmitter_spec.rb
+++ b/spec/lib/appsignal/transmitter_spec.rb
@@ -1,6 +1,10 @@
 describe Appsignal::Transmitter do
+  let(:options) { {} }
   let(:config) do
-    build_config(:options => { :hostname => "app1.local" }, :logger => Logger.new(log))
+    build_config(
+      :options => { :hostname => "app1.local" }.merge(options),
+      :logger => Logger.new(log)
+    )
   end
   let(:base_uri) { "action" }
   let(:log) { StringIO.new }
@@ -89,9 +93,7 @@
 
     context "with ca_file_path config option set" do
       context "when file does not exist" do
-        before do
-          config.config_hash[:ca_file_path] = File.join(resources_dir, "cacert.pem")
-        end
+        let(:options) { { :ca_file_path => File.join(resources_dir, "cacert.pem") } }
 
         it "ignores the config and logs a warning" do
           expect(response).to be_kind_of(Net::HTTPResponse)
@@ -102,9 +104,7 @@
       end
 
       context "when not existing file" do
-        before do
-          config.config_hash[:ca_file_path] = File.join(tmp_dir, "ca_file_that_does_not_exist")
-        end
+        let(:options) { { :ca_file_path => File.join(tmp_dir, "ca_file_that_does_not_exist") } }
 
         it "ignores the config and logs a warning" do
           expect(response).to be_kind_of(Net::HTTPResponse)
@@ -116,8 +116,8 @@
 
       context "when not readable file" do
         let(:file) { File.join(tmp_dir, "ca_file") }
+        let(:options) { { :ca_file_path => file } }
         before do
-          config.config_hash[:ca_file_path] = file
           File.open(file, "w") { |f| f.chmod 0o000 }
         end
 
diff --git a/spec/lib/appsignal_spec.rb b/spec/lib/appsignal_spec.rb
index c75713a7..d401dc80 100644
--- a/spec/lib/appsignal_spec.rb
+++ b/spec/lib/appsignal_spec.rb
@@ -376,7 +376,14 @@ def on_load
     end
 
     context "when config is loaded" do
-      before { Appsignal.configure(:production, :root_path => project_fixture_path) }
+      let(:options) { {} }
+      before do
+        configure(
+          :env => :production,
+          :root_path => project_fixture_path,
+          :options => options
+        )
+      end
 
       it "should initialize logging" do
         Appsignal.start
@@ -395,7 +402,7 @@ def on_load
           Appsignal.config[:ignore_actions] << "my action"
         end
         expect_frozen_error do
-          Appsignal.config.config_hash[:ignore_actions] << "my action"
+          Appsignal.config[:ignore_actions] << "my action"
         end
         expect_frozen_error do
           Appsignal.config.config_hash.merge!(:option => :value)
@@ -410,8 +417,8 @@ def expect_frozen_error(&block)
       end
 
       context "when allocation tracking has been enabled" do
+        let(:options) { { :enable_allocation_tracking => true } }
         before do
-          Appsignal.config.config_hash[:enable_allocation_tracking] = true
           capture_environment_metadata_report_calls
         end
 
@@ -426,12 +433,12 @@ def expect_frozen_error(&block)
       end
 
       context "when allocation tracking has been disabled" do
+        let(:options) { { :enable_allocation_tracking => false } }
         before do
-          Appsignal.config.config_hash[:enable_allocation_tracking] = false
           capture_environment_metadata_report_calls
         end
 
-        it "should not install the allocation event hook" do
+        it "doesn't install the allocation event hook" do
           expect(Appsignal::Extension).not_to receive(:install_allocation_event_hook)
           Appsignal.start
           expect_not_environment_metadata("ruby_allocation_tracking_enabled")
@@ -439,22 +446,18 @@ def expect_frozen_error(&block)
       end
 
       context "when minutely metrics has been enabled" do
-        before do
-          Appsignal.config.config_hash[:enable_minutely_probes] = true
-        end
+        let(:options) { { :enable_minutely_probes => true } }
 
-        it "should start minutely" do
+        it "starts minutely probes" do
           expect(Appsignal::Probes).to receive(:start)
           Appsignal.start
         end
       end
 
       context "when minutely metrics has been disabled" do
-        before do
-          Appsignal.config.config_hash[:enable_minutely_probes] = false
-        end
+        let(:options) { { :enable_minutely_probes => false } }
 
-        it "should not start minutely" do
+        it "does not start minutely probes" do
           expect(Appsignal::Probes).to_not receive(:start)
           Appsignal.start
         end
diff --git a/spec/support/helpers/config_helpers.rb b/spec/support/helpers/config_helpers.rb
index 3fcce928..30f4b522 100644
--- a/spec/support/helpers/config_helpers.rb
+++ b/spec/support/helpers/config_helpers.rb
@@ -30,14 +30,18 @@ def build_config(
   end
   module_function :build_config
 
-  def start_agent(env: "production", options: {}, internal_logger: nil)
+  def configure(env: :default, root_path: project_fixture_path, options: {})
     env = "production" if env == :default
     env ||= "production"
-    Appsignal.configure(env, :root_path => project_fixture_path) do |config|
+    Appsignal.configure(env, :root_path => root_path) do |config|
       options.each do |option, value|
         config.send("#{option}=", value)
       end
     end
+  end
+
+  def start_agent(env: :default, options: {}, internal_logger: nil)
+    configure(:env => env, :options => options)
     Appsignal.start
     Appsignal.internal_logger = internal_logger if internal_logger
   end