diff --git a/tests/test_common.cc b/tests/test_common.cc
index 68e28e7c..a8777020 100644
--- a/tests/test_common.cc
+++ b/tests/test_common.cc
@@ -3,9 +3,111 @@
 #include <filesystem>
 #include <string>
 #include <common/cmdlib.hh>
+#include <common/bspfile.hh>
+#include <common/bspfile_q1.hh>
+#include <common/bspfile_q2.hh>
 
 TEST_CASE("StripFilename", "[common]")
 {
     REQUIRE("/home/foo" == fs::path("/home/foo/bar.txt").parent_path());
     REQUIRE("" == fs::path("bar.txt").parent_path());
 }
+
+TEST_CASE("q1 contents", "[common][!mayfail]")
+{
+    auto* game_q1 = bspver_q1.game;
+
+    const auto solid = game_q1->create_solid_contents();
+    const auto detail_solid = game_q1->create_detail_solid_contents(solid);
+    const auto detail_fence = game_q1->create_detail_fence_contents(solid);
+    const auto detail_illusionary = game_q1->create_detail_illusionary_contents(solid);
+
+    const std::array test_contents{
+        contentflags_t{CONTENTS_EMPTY},
+        contentflags_t{CONTENTS_SOLID},
+        contentflags_t{CONTENTS_WATER},
+        contentflags_t{CONTENTS_SLIME},
+        contentflags_t{CONTENTS_LAVA},
+        contentflags_t{CONTENTS_SKY},
+
+        detail_solid,
+        detail_fence,
+        detail_illusionary
+    };
+
+    SECTION("solid combined with others") {
+        CHECK(solid.native == CONTENTS_SOLID);
+        CHECK(!solid.game_data.has_value());
+
+        for (const auto &c : test_contents) {
+            auto combined = game_q1->combine_contents(solid, c);
+
+            CHECK(combined.native == CONTENTS_SOLID);
+            CHECK(combined.is_solid(game_q1));
+
+            CHECK(!combined.is_any_detail(game_q1));
+        }
+    }
+
+    SECTION("detail_illusionary plus water") {
+        auto combined = game_q1->combine_contents(detail_illusionary, contentflags_t{CONTENTS_WATER});
+
+        CHECK(combined.native == CONTENTS_WATER);
+        CHECK(combined.is_detail_illusionary(game_q1));
+    }
+}
+
+TEST_CASE("q2 contents", "[common]")
+{
+    const std::array test_contents {
+        contentflags_t{Q2_CONTENTS_EMPTY},
+        contentflags_t{Q2_CONTENTS_SOLID},
+        contentflags_t{Q2_CONTENTS_WINDOW},
+        contentflags_t{Q2_CONTENTS_AUX},
+        contentflags_t{Q2_CONTENTS_LAVA},
+        contentflags_t{Q2_CONTENTS_SLIME},
+        contentflags_t{Q2_CONTENTS_WATER},
+        contentflags_t{Q2_CONTENTS_MIST},
+
+        contentflags_t{Q2_CONTENTS_DETAIL | Q2_CONTENTS_SOLID},
+        contentflags_t{Q2_CONTENTS_DETAIL | Q2_CONTENTS_WINDOW},
+        contentflags_t{Q2_CONTENTS_DETAIL | Q2_CONTENTS_AUX},
+        contentflags_t{Q2_CONTENTS_DETAIL | Q2_CONTENTS_LAVA},
+        contentflags_t{Q2_CONTENTS_DETAIL | Q2_CONTENTS_SLIME},
+        contentflags_t{Q2_CONTENTS_DETAIL | Q2_CONTENTS_WATER},
+        contentflags_t{Q2_CONTENTS_DETAIL | Q2_CONTENTS_MIST}
+    };
+
+    auto* game_q2 = bspver_q2.game;
+
+    SECTION("solid combined with others"){
+        auto solid = game_q2->create_solid_contents();
+        CHECK(solid.native == Q2_CONTENTS_SOLID);
+        CHECK(!solid.game_data.has_value());
+
+        for (const auto &c : test_contents) {
+            // solid is treated specially in Q2 and wipes out any other content
+            // flags when combined
+            auto combined = game_q2->combine_contents(solid, c);
+
+            CHECK(combined.native == Q2_CONTENTS_SOLID);
+            CHECK(!combined.game_data.has_value());
+            CHECK(combined.is_solid(game_q2));
+        }
+    }
+
+    SECTION("water combined with others"){
+        contentflags_t water{Q2_CONTENTS_WATER};
+
+        for (const auto &c : test_contents) {
+            auto combined = game_q2->combine_contents(water, c);
+            CHECK(!combined.game_data.has_value());
+
+            DYNAMIC_SECTION("water combined with " << c.to_string(game_q2)) {
+                if (!(c.native & Q2_CONTENTS_SOLID)) {
+                    CHECK(combined.native == (Q2_CONTENTS_WATER | c.native));
+                }
+            }
+        }
+    }
+}