Allow 5 digits account numbers for Australian bank details

It appears that 5-digits account numbers are valid accounts in Australia.

lib/ibandit/local_details_cleaner.rb

@@ -65,8 +65,8 @@ def self.clean_au_details(local_details)
       # Account number may be up to 10 digits long.
       # Add leading zeros to account number if < 10 digits.
       #
-      # Minimum account_number length is 6
-      return {} unless local_details[:account_number].length >= 6
+      # Minimum account_number length is 5
+      return {} unless local_details[:account_number].length >= 5
 
       {
         branch_code:    local_details[:branch_code].delete("-"),

spec/ibandit/iban_spec.rb

@@ -185,6 +185,23 @@
         its(:to_s) { is_expected.to eq("") }
       end
 
+      context "and a 5 digit account number" do
+        let(:account_number) { "12345" }
+
+        its(:country_code) { is_expected.to eq("AU") }
+        its(:bank_code) { is_expected.to be_nil }
+        its(:branch_code) { is_expected.to eq("123456") }
+        its(:account_number) { is_expected.to eq("0000012345") }
+        its(:swift_bank_code) { is_expected.to be_nil }
+        its(:swift_branch_code) { is_expected.to eq("123456") }
+        its(:swift_account_number) { is_expected.to eq("0000012345") }
+        its(:swift_national_id) { is_expected.to eq("123456") }
+        its(:iban) { is_expected.to be_nil }
+        its(:pseudo_iban) { is_expected.to eq("AUZZ1234560000012345") }
+        its(:valid?) { is_expected.to eq(true) }
+        its(:to_s) { is_expected.to eq("") }
+      end
+
       context "and a 6 digit account number" do
         let(:account_number) { "123456" }
 
@@ -300,6 +317,25 @@
       end
     end
 
+    context "when the input is an account number too short for Australia" do
+      let(:arg) do
+        {
+          country_code: "AU",
+          branch_code: "123456",
+          account_number: "1234",
+        }
+      end
+
+      its(:iban) { is_expected.to be_nil }
+      its(:pseudo_iban) { is_expected.to eq("AUZZ123456______1234") }
+      it "is invalid and has the correct errors" do
+        expect(subject.valid?).to eq(false)
+        expect(subject.errors).to eq(
+          account_number: "is the wrong length (should be 10 characters)",
+        )
+      end
+    end
+
     context "when the input is invalid local details for Australia" do
       let(:arg) do
         {