[cli] fix no-os case in table formatter output for FindReply

Author: Saviq

src/client/cli/formatter/table_formatter.cpp

@@ -156,7 +156,7 @@ std::string mp::TableFormatter::format(const FindReply& reply) const
         fmt::format_to(buf, "{:<24}{:<18}{:<17}{:<}\n",
                        (alias->remote_name().empty() ? "" : alias->remote_name() + ":") + alias->alias(),
                        fmt::format("{}", fmt::join(aliases.cbegin() + 1, aliases.cend(), ",")), image.version(),
-                       fmt::format("{} {}", image.os(), image.release()));
+                       fmt::format("{}{}", image.os().empty() ? ""  : image.os() + " ", image.release()));
     }
 
     return fmt::to_string(buf);

tests/test_output_formatter.cpp

@@ -176,6 +176,21 @@ auto construct_find_one_reply()
     return reply;
 }
 
+auto construct_find_one_reply_no_os()
+{
+    auto reply = mp::FindReply();
+
+    auto image_entry = reply.add_images_info();
+    image_entry->set_release("Snapcraft builder for core16");
+    image_entry->set_version("20190520");
+
+    auto alias_entry = image_entry->add_aliases_info();
+    alias_entry->set_alias("core18");
+    alias_entry->set_remote_name("snapcraft");
+
+    return reply;
+}
+
 auto construct_find_multiple_replies()
 {
     auto reply = mp::FindReply();
@@ -400,6 +415,19 @@ TEST_F(TableFormatter, filtered_aliases_in_find_output)
     EXPECT_EQ(output, expected_output);
 }
 
+TEST_F(TableFormatter, well_formatted_empty_os_find_output)
+{
+    mp::TableFormatter formatter;
+    const auto reply = construct_find_one_reply_no_os();
+
+    auto expected_output = "Image                   Aliases           Version          Description\n"
+                           "snapcraft:core18        eoan,devel        20190516         Snapcraft builder for core18\n";
+
+    auto output = formatter.format(reply);
+
+    EXPECT_EQ(output, expected_output);
+}
+
 TEST_F(TableFormatter, no_images_find_output)
 {
     mp::FindReply find_reply;