Fix min/max also test (#1646)

Co-authored-by: wixoa <[email protected]>

Content.Tests/DMProject/Tests/Math/minmax.dm

@@ -0,0 +1,22 @@
+/proc/RunTest()
+    ASSERT(min(1,2,3) == 1)
+    ASSERT(min(null, 1) == null)
+    ASSERT(min(null, -1) == -1)
+    ASSERT(min(1, null) == null)
+    ASSERT(min(-1, null) == -1)
+    ASSERT(min(1, null) == null)
+    ASSERT(min(0, null) == null)
+    ASSERT(min(null, 0) == 0)
+    ASSERT(min("a","b","c")=="a")
+    ASSERT(min("b","a","c")=="a")
+
+    ASSERT(max(1,2,3) == 3)
+    ASSERT(max(null, 1) == 1)
+    ASSERT(max(null, -1) == null)
+    ASSERT(max(1,null) == 1)
+    ASSERT(max(-1,null) == null)
+    ASSERT(max(1, null) == 1)
+    ASSERT(max(0, null) == null)
+    ASSERT(max(null, 0) == 0)
+    ASSERT(max("a","b","c")=="c")
+    ASSERT(max("b","a","c")=="c")

OpenDreamRuntime/Procs/Native/DreamProcNativeRoot.cs

@@ -1473,14 +1473,19 @@ public static DreamValue NativeProc_md5(NativeProc.Bundle bundle, DreamObject? s
         }
 
         private static DreamValue MinComparison(DreamValue min, DreamValue value) {
-            if (value.TryGetValueAsFloat(out var lFloat) && min.TryGetValueAsFloat(out var rFloat)) {
-                if (lFloat < rFloat)
+            if (value.TryGetValueAsFloat(out var lFloat)) {
+                if (min.IsNull && lFloat <= 0)
                     min = value;
-            } else if (value.TryGetValueAsString(out var lString) && min.TryGetValueAsString(out var rString)) {
-                if (string.Compare(lString, rString, StringComparison.Ordinal) < 0)
+                else if (min.TryGetValueAsFloat(out var rFloat) && lFloat <= rFloat)
                     min = value;
             } else if (value.IsNull) {
-                min = value;
+                if (min.TryGetValueAsFloat(out var minFloat) && minFloat >= 0)
+                    min = value;
+            } else if (value.TryGetValueAsString(out var lString)) {
+                if (min.IsNull)
+                    min = value;
+                else if (min.TryGetValueAsString(out var rString) && string.Compare(lString, rString, StringComparison.Ordinal) <= 0)
+                    min = value;
             } else {
                 throw new Exception($"Cannot compare {min} and {value}");
             }