Report exact sizes in the insufficient-disk-space error

Integer division truncated the GB figures (1.9 GB read as 1 GB),
understating the requirement. Use number_to_human_size instead.

Author: jeremy

app/models/account/import.rb

@@ -96,10 +96,14 @@ def ensure_sufficient_disk_space
       available = available_disk_space(path)
 
       if available && available < required
-        raise InsufficientDiskSpaceError, "import needs ~#{required / 1.gigabyte} GB free, found #{available / 1.gigabyte} GB"
+        raise InsufficientDiskSpaceError, "import needs ~#{human_size(required)} free, found #{human_size(available)}"
       end
     end
 
+    def human_size(bytes)
+      ActiveSupport::NumberHelper.number_to_human_size(bytes)
+    end
+
     def available_disk_space(path)
       fields = `df -Pk #{Shellwords.escape(path)} 2>/dev/null`.lines.last.to_s.split
       # Anchor on the capacity percentage — the only NN% field — since spaces in

test/models/account/import_test.rb

@@ -225,7 +225,7 @@ class Account::ImportTest < ActiveSupport::TestCase
     import.stubs(:available_disk_space).returns(import.file.blob.byte_size)
 
     error = assert_raises(Account::Import::InsufficientDiskSpaceError) { import.check }
-    assert_match(/GB free/, error.message)
+    assert_match(/import needs ~.+ free, found/, error.message)
     assert import.reload.failed_due_to_insufficient_disk_space?
   end