Change upload to no longer silently convert Strings to StringIO

The interface for this will change to add a `stream` version, similar to #63.

To prepare for that we simplify the `upload` method

lib/bucket_store/key_storage.rb

@@ -59,32 +59,24 @@ def download
     end
 
     # Uploads the given file to the reference key location.
-    # If the File is a file like object then upload as is.
-    # If the file variable is actually a string then treat is as the file
-    # contents and upload as is.
     #
     # If the `key` already exists, its content will be replaced by the one in input.
     #
-    # @param [String or File like object] file The file like object to upload or a String
-    #         with the contents
+    # @param [String] content Contents of the file
     # @return [String] The final `key` where the content has been uploaded
     # @example Upload a file
     #   BucketStore.for("inmemory://bucket/file.xml").upload!("hello world")
-    def upload!(file)
+    def upload!(content)
       raise ArgumentError, "Key cannot be empty" if key.empty?
 
-      if file.instance_of?(String)
-        file = StringIO.new(file)
-      end
-
       BucketStore.logger.info(event: "key_storage.upload_started",
                               **log_context)
 
       start = BucketStore::Timing.monotonic_now
       result = adapter.upload!(
         bucket: bucket,
         key: key,
-        file: file,
+        file: StringIO.new(content),
       )
 
       BucketStore.logger.info(event: "key_storage.upload_finished",

spec/bucket_store/key_storage_spec.rb

@@ -115,33 +115,6 @@ def build_for(key)
           to raise_error(ArgumentError, /key cannot be empty/i)
       end
     end
-
-    context "when given a file like object" do
-      let(:file) { StringIO.new("hello") }
-
-      it "uploads the given file" do
-        expect(build_for("inmemory://bucket/file1").upload!(file)).
-          to eq("inmemory://bucket/file1")
-      end
-
-      it "logs the operation" do
-        expect(BucketStore.logger).to receive(:info).with(
-          hash_including(event: "key_storage.upload_started"),
-        )
-        expect(BucketStore.logger).to receive(:info).with(
-          hash_including(event: "key_storage.upload_finished"),
-        )
-
-        build_for("inmemory://bucket/file1").upload!(file)
-      end
-
-      context "when we try to upload a bucket" do
-        it "raises an error" do
-          expect { build_for("inmemory://bucket").upload!(file) }.
-            to raise_error(ArgumentError, /key cannot be empty/i)
-        end
-      end
-    end
   end
 
   describe "#delete!" do