Test case failures.

mihxil · Dec 16, 2024 · 34a09de · 34a09de
1 parent 0826e29
commit 34a09de
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Showing 2 changed files with 17 additions and 9 deletions.
diff --git a/mihxil-algebra/src/main/java/org/meeuw/math/abstractalgebra/dihedral/DihedralGroup.java b/mihxil-algebra/src/main/java/org/meeuw/math/abstractalgebra/dihedral/DihedralGroup.java
@@ -9,6 +9,8 @@
 import org.meeuw.math.Example;
 import org.meeuw.math.abstractalgebra.*;
 
+import org.meeuw.math.exceptions.InvalidElementCreationException;
+
 import static org.meeuw.math.text.TextUtils.subscript;
 
 /**
@@ -38,13 +40,19 @@ private DihedralGroup(int n) {
     }
 
     public DihedralSymmetry r(int k) {
+        if (k < 0 || k >= n) {
+            throw new InvalidElementCreationException("! 0 <= %d < k".formatted(k));
+        }
         if (rcache[k] == null) {
             rcache[k] = DihedralSymmetry.r(k, this);
         }
         return rcache[k];
     }
 
     public DihedralSymmetry s(int k) {
+        if (k < 0 || k >= n) {
+            throw new InvalidElementCreationException("! 0 <= %d < k".formatted(k));
+        }
         if (scache[k] == null) {
             scache[k] = DihedralSymmetry.s(k, this);
         }

diff --git a/...algebra/src/test/java/org/meeuw/test/math/abstractalgebra/dihedral/DihedralGroupTest.java b/...algebra/src/test/java/org/meeuw/test/math/abstractalgebra/dihedral/DihedralGroupTest.java
@@ -37,15 +37,15 @@ public void s() {
     @Test
     public void illegal() {
         DihedralGroup group = DihedralGroup.of(4);
-        assertThatThrownBy(() -> {
-            group.s(4);
-        }).isInstanceOf(InvalidElementCreationException.class);
-        assertThatThrownBy(() -> {
-            group.r(4);
-        }).isInstanceOf(InvalidElementCreationException.class);
-        assertThatThrownBy(() -> {
-            group.r(-1);
-        }).isInstanceOf(InvalidElementCreationException.class);
+        assertThatThrownBy(() ->
+            group.s(4)
+        ).isInstanceOf(InvalidElementCreationException.class);
+        assertThatThrownBy(() ->
+            group.r(4)
+        ).isInstanceOf(InvalidElementCreationException.class);
+        assertThatThrownBy(() ->
+            group.r(-1)
+        ).isInstanceOf(InvalidElementCreationException.class);
 
     }