terminal: fix up some tests to be more robust

src/terminal/Parser.zig

@@ -193,7 +193,7 @@ pub const Action = union(enum) {
 /// Maximum number of intermediate characters during parsing. This is
 /// 4 because we also use the intermediates array for UTF8 decoding which
 /// can be at most 4 bytes.
-const MAX_INTERMEDIATE = 4;
+pub const MAX_INTERMEDIATE = 4;
 
 /// Maximum number of CSI parameters. This is arbitrary. Practically, the
 /// only CSI command that uses more than 3 parameters is the SGR command
@@ -949,17 +949,17 @@ test "csi: too many params" {
     }
 }
 
-test "csi: 17 parameters" {
-    // Test with exactly 17 parameters (the Kakoune case)
+test "csi: sgr with up to our max parameters" {
+    for (1..MAX_PARAMS + 1) |max| {
         var p = init();
         _ = p.next(0x1B);
         _ = p.next('[');
-    // Build 17 parameters separated by semicolons
-    for (0..16) |_| {
+
+        for (0..max - 1) |_| {
             _ = p.next('1');
             _ = p.next(';');
         }
-    _ = p.next('2'); // 17th parameter
+        _ = p.next('2');
 
         {
             const a = p.next('H');
@@ -969,8 +969,32 @@ test "csi: 17 parameters" {
             try testing.expect(a[2] == null);
 
             const csi = a[1].?.csi_dispatch;
-        try testing.expectEqual(@as(usize, 17), csi.params.len);
-        try testing.expectEqual(@as(u16, 2), csi.params[16]);
+            try testing.expectEqual(@as(usize, max), csi.params.len);
+            try testing.expectEqual(@as(u16, 2), csi.params[max - 1]);
+        }
+    }
+}
+
+test "csi: sgr beyond our max drops it" {
+    // Has to be +2 for the loops below
+    const max = MAX_PARAMS + 2;
+
+    var p = init();
+    _ = p.next(0x1B);
+    _ = p.next('[');
+
+    for (0..max - 1) |_| {
+        _ = p.next('1');
+        _ = p.next(';');
+    }
+    _ = p.next('2');
+
+    {
+        const a = p.next('H');
+        try testing.expect(p.state == .ground);
+        try testing.expect(a[0] == null);
+        try testing.expect(a[1] == null);
+        try testing.expect(a[2] == null);
     }
 }