adding lots of unit tests, improving image sampling, adding image sampling deref

test/arrays.zig

@@ -33,3 +33,42 @@ test "Simple array" {
         },
     });
 }
+
+test "Array fold" {
+    const allocator = std.testing.allocator;
+    const shader =
+        \\ [nzsl_version("1.1")]
+        \\ module;
+        \\
+        \\ struct FragOut
+        \\ {
+        \\     [location(0)] color: vec4[f32]
+        \\ }
+        \\
+        \\ [entry(frag)]
+        \\ fn main() -> FragOut
+        \\ {
+        \\     let values = array[f32](1.0, 2.0, 3.0, 4.0);
+        \\     let sum = 0.0;
+        \\     let weighted = 0.0;
+        \\     for i in u32(0) -> values.Size()
+        \\     {
+        \\         sum += values[i];
+        \\         weighted += values[i] * f32(i + 1);
+        \\     }
+        \\
+        \\     let output: FragOut;
+        \\     output.color = vec4[f32](sum, weighted, values[2], f32(values.Size()));
+        \\     return output;
+        \\ }
+    ;
+    const code = try compileNzsl(allocator, shader);
+    defer allocator.free(code);
+
+    try case.expect(.{
+        .source = code,
+        .expected_outputs = &.{
+            std.mem.asBytes(&[_]f32{ 10.0, 30.0, 3.0, 4.0 }),
+        },
+    });
+}