[visual] guard quadblitter tests with check

src/tests/visual.cpp

@@ -106,6 +106,7 @@ TEST_CASE("Visual") {
   // write a checkerboard pattern and verify the NCBLIT_2x2 output
   SUBCASE("Quadblitter") {
     if(notcurses_canutf8(nc_)){
+      if(nc_->tcache.quadrants){
         constexpr int DIMY = 10;
         constexpr int DIMX = 11; // odd number to get checkerboard effect
         auto rgba = new uint32_t[DIMY * DIMX];
@@ -142,10 +143,12 @@ TEST_CASE("Visual") {
         delete[] rgba;
       }
     }
+  }
 
   // close-in verification of each quadblitter output EGC 
   SUBCASE("QuadblitterEGCs") {
     if(notcurses_canutf8(nc_)){
+      if(nc_->tcache.quadrants){
         // there are 16 configurations, each mapping four (2x2) pixels
         int DIMX = 32;
         int DIMY = 2;
@@ -216,10 +219,12 @@ TEST_CASE("Visual") {
         delete[] rgba;
       }
     }
+  }
 
   // quadblitter with all 4 colors equal ought generate space
   SUBCASE("Quadblitter4Same") {
     if(notcurses_canutf8(nc_)){
+      if(nc_->tcache.quadrants){
         const uint32_t pixels[4] = { htole(0xff605040), htole(0xff605040), htole(0xff605040), htole(0xff605040) };
         auto ncv = ncvisual_from_rgba(pixels, 2, 2 * sizeof(*pixels), 2);
         REQUIRE(nullptr != ncv);
@@ -252,10 +257,12 @@ TEST_CASE("Visual") {
         ncvisual_destroy(ncv);
       }
     }
+  }
 
   // quadblitter with three pixels equal ought generate three-quarter block
   SUBCASE("Quadblitter3Same") {
     if(notcurses_canutf8(nc_)){
+      if(nc_->tcache.quadrants){
         const uint32_t pixels[4][4] = {
           { htole(0xffcccccc), htole(0xff605040), htole(0xff605040), htole(0xff605040) },
           { htole(0xff605040), htole(0xffcccccc), htole(0xff605040), htole(0xff605040) },
@@ -295,10 +302,12 @@ TEST_CASE("Visual") {
         }
       }
     }
+  }
 
   // quadblitter with two sets of two equal pixels
   SUBCASE("Quadblitter2Pairs") {
     if(notcurses_canutf8(nc_)){
+      if(nc_->tcache.quadrants){
         const uint32_t pixels[6][4] = {
           { htole(0xffcccccc), htole(0xffcccccc), htole(0xff605040), htole(0xff605040) },
           { htole(0xffcccccc), htole(0xff605040), htole(0xffcccccc), htole(0xff605040) },
@@ -345,10 +354,12 @@ TEST_CASE("Visual") {
         }
       }
     }
+  }
 
   // quadblitter with one pair plus two split
   SUBCASE("Quadblitter1Pair") {
     if(notcurses_canutf8(nc_)){
+      if(nc_->tcache.quadrants){
         const uint32_t pixels[6][4] = {
           { htole(0xffcccccc), htole(0xff444444), htole(0xff605040), htole(0xff605040) },
           { htole(0xff444444), htole(0xff605040), htole(0xffcccccc), htole(0xff605040) },
@@ -395,10 +406,12 @@ TEST_CASE("Visual") {
         }
       }
     }
+  }
 
   // quadblitter with one pair plus two split
   SUBCASE("QuadblitterAllDifferent") {
     if(notcurses_canutf8(nc_)){
+      if(nc_->tcache.quadrants){
         const uint32_t pixels[6][4] = {
           { htole(0xffdddddd), htole(0xff000000), htole(0xff111111), htole(0xff222222) },
           { htole(0xff000000), htole(0xff111111), htole(0xffdddddd), htole(0xff222222) },
@@ -439,6 +452,7 @@ TEST_CASE("Visual") {
         }
       }
     }
+  }
 
 #ifndef NOTCURSES_USE_MULTIMEDIA
   SUBCASE("VisualDisabled"){