Add IntervalTest

build.gradle

@@ -16,6 +16,7 @@ dependencies {
     testImplementation platform('org.junit:junit-bom:5.10.0')
     testImplementation 'org.junit.jupiter:junit-jupiter'
     testImplementation 'org.hamcrest:hamcrest:3.0'
+    testImplementation 'org.assertj:assertj-core:3.26.3'
 }
 
 test {

src/main/java/by/andd3dfx/math/Interval.java

@@ -31,6 +31,10 @@ public double x2() {
         return x2;
     }
 
+    public double h() {
+        return h;
+    }
+
     public int n() {
         return n;
     }

src/test/java/by/andd3dfx/math/IntervalTest.java

@@ -0,0 +1,89 @@
+package by.andd3dfx.math;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
+
+class IntervalTest {
+
+    @Test
+    void defaultConstructor() {
+        var interval = new Interval();
+
+        assertThat(interval.x1()).isEqualTo(0.0);
+        assertThat(interval.x2()).isEqualTo(1.0);
+        assertThat(interval.h()).isEqualTo(1.0);
+        assertThat(interval.n()).isEqualTo(1);
+    }
+
+    @Test
+    void paramsConstructorWithN() {
+        var interval = new Interval(2.5, 10.5, 10);
+
+        assertThat(interval.x1()).isEqualTo(2.5);
+        assertThat(interval.x2()).isEqualTo(10.5);
+        assertThat(interval.h()).isEqualTo(0.8);
+        assertThat(interval.n()).isEqualTo(10);
+    }
+
+    @Test
+    void paramsConstructorWithH() {
+        var interval = new Interval(2.5, 10.5, 0.1);
+
+        assertThat(interval.x1()).isEqualTo(2.5);
+        assertThat(interval.x2()).isEqualTo(10.5);
+        assertThat(interval.h()).isEqualTo(0.1);
+        assertThat(interval.n()).isEqualTo(80);
+    }
+
+    @Test
+    void rebornWithN() {
+        var interval = new Interval(2.5, 10.5, 10);
+
+        interval.reborn(5.0, 10.0, 100);
+
+        assertThat(interval.x1()).isEqualTo(5.0);
+        assertThat(interval.x2()).isEqualTo(10.0);
+        assertThat(interval.h()).isEqualTo(0.05);
+        assertThat(interval.n()).isEqualTo(100);
+    }
+
+    @Test
+    void rebornWithH() {
+        var interval = new Interval(2.5, 10.5, 10);
+
+        interval.reborn(5.0, 10.0, 0.2);
+
+        assertThat(interval.x1()).isEqualTo(5.0);
+        assertThat(interval.x2()).isEqualTo(10.0);
+        assertThat(interval.h()).isEqualTo(0.2);
+        assertThat(interval.n()).isEqualTo(25);
+    }
+
+    @Test
+    void x() {
+        var interval = new Interval(2.0, 12.0, 5);
+
+        assertThat(interval.x(0)).isEqualTo(2.0);
+        assertThat(interval.x(2)).isEqualTo(6.0);
+    }
+
+    @Test
+    void i() {
+        var interval = new Interval(2.0, 12.0, 5);
+
+        assertThat(interval.i(2.0)).isEqualTo(0);
+        assertThat(interval.i(5.9)).isEqualTo(1);
+        assertThat(interval.i(6.1)).isEqualTo(2);
+    }
+
+    @Test
+    void saveFuncSimple() {
+        // TODO
+    }
+
+    @Test
+    void saveFuncForParameterizedXAndY() {
+        // TODO
+    }
+}