Failing test case

If chunkSize doesn't divide contentSize evenly, and chunkSize < 0.5*contentSize,
we try to download a chunk bigger than chunkSize.  This should not be possible.

pkg/download/buffer_unit_test.go

@@ -45,7 +45,7 @@ func newTestServer(t *testing.T, content []byte) *httptest.Server {
 // TODO: Implement the test
 // func TestGetFileSizeFromContentRange(t *testing.T) {}
 func TestFileToBufferChunkCountExceedsMaxChunks(t *testing.T) {
-	contentSize := int64(humanize.KByte)
+	contentSize := int64(humanize.KiByte)
 	content := generateTestContent(contentSize)
 	server := newTestServer(t, content)
 	defer server.Close()
@@ -98,9 +98,9 @@ func TestFileToBufferChunkCountExceedsMaxChunks(t *testing.T) {
 			maxConcurrency: 2,
 		},
 		{
-			// humanize.KByte = 1024, remainder will result in 1024/10 = 102 chunks, max-chunks is set to 25
+			// humanize.KByte = 1024, remainder will result in 1024/10 = 102 chunks, concurrency is set to 25
 			// resulting in a chunkSize of 41
-			name:           "many chunks, low maxChunks",
+			name:           "many chunks, low maxConcurrency",
 			chunkSize:      10,
 			maxConcurrency: 25,
 		},

pkg/download/buffered_reader.go

@@ -42,6 +42,11 @@ func (b *bufferedReader) done() {
 
 func (b *bufferedReader) downloadBody(resp *http.Response) error {
 	expectedBytes := resp.ContentLength
+
+	if expectedBytes > int64(b.buf.Cap()) {
+		b.err = fmt.Errorf("Tried to download 0x%x bytes to a 0x%x-sized buffer", expectedBytes, b.buf.Cap())
+		return b.err
+	}
 	n, err := b.buf.ReadFrom(resp.Body)
 	if err != nil && err != io.EOF {
 		b.err = fmt.Errorf("error reading response for %s: %w", resp.Request.URL.String(), err)