diff --git a/test/aprsme/db_optimizer_test.exs b/test/aprsme/db_optimizer_test.exs
index b6c5e08..83ea9d1 100644
--- a/test/aprsme/db_optimizer_test.exs
+++ b/test/aprsme/db_optimizer_test.exs
@@ -170,4 +170,24 @@ defmodule Aprsme.DbOptimizerTest do
       assert :error = DbOptimizer.vacuum_table("packets", analyze: false)
     end
   end
+
+  describe "validate_identifier! and quote_identifier via atoms" do
+    test "analyze_table accepts an atom name (converts to string)" do
+      # Exercises validate_identifier!(atom) → string version and
+      # quote_identifier(atom) → string version (both defp helpers).
+      result = DbOptimizer.analyze_table(:packets)
+      assert result == :ok or result == :error
+    end
+
+    test "analyze_table returns :error for invalid identifier characters" do
+      # validate_identifier! raises ArgumentError, but the surrounding rescue
+      # in analyze_table converts it to :error.
+      assert :error = DbOptimizer.analyze_table("not-a-valid;identifier")
+    end
+
+    test "vacuum_table accepts atom names" do
+      result = DbOptimizer.vacuum_table(:packets, full: false, analyze: false)
+      assert result == :ok or result == :error
+    end
+  end
 end
diff --git a/test/aprsme_web/aprs_symbol_test.exs b/test/aprsme_web/aprs_symbol_test.exs
index 1305fe5..7d49955 100644
--- a/test/aprsme_web/aprs_symbol_test.exs
+++ b/test/aprsme_web/aprs_symbol_test.exs
@@ -149,6 +149,46 @@ defmodule AprsmeWeb.AprsSymbolTest do
     end
   end
 
+  describe "render_marker_html/4 default arg coverage" do
+    test "renders without callsign or size args (uses defaults)" do
+      html = AprsSymbol.render_marker_html("/", ">")
+      assert is_binary(html)
+      assert html =~ "background-image"
+    end
+
+    test "renders without callsign with explicit size" do
+      html = AprsSymbol.render_marker_html("/", ">", nil, 32)
+      assert is_binary(html)
+    end
+
+    test "renders an overlay marker without callsign" do
+      html = AprsSymbol.render_marker_html("A", ">", nil)
+      assert is_binary(html)
+    end
+  end
+
+  describe "render_style/3 default arg coverage" do
+    test "renders an inline style string with default size" do
+      style = AprsSymbol.render_style("/", ">")
+      assert is_binary(style)
+      assert style =~ "background-image"
+    end
+
+    test "renders an inline style string with explicit size" do
+      style = AprsSymbol.render_style("/", ">", 64)
+      assert style =~ "64px"
+    end
+  end
+
+  describe "get_symbol_code_ord fallback via get_sprite_info" do
+    test "non-binary symbol_code yields default ord (?)" do
+      # nil/integer symbol_code lands on the catch-all in get_symbol_code_ord/1
+      info = AprsSymbol.get_sprite_info("/", nil)
+      assert is_map(info)
+      assert is_binary(info.sprite_file)
+    end
+  end
+
   describe "normalize helpers" do
     test "normalize_symbol_table maps overlay characters to ']' table" do
       # Single alphanumeric → overlay table