one more solution

README.md

@@ -14,3 +14,4 @@ To reformat code, run the script:
 
 `bash reformat_all_code.sh`
 
+Run this command before pushing any code changes. If formatting is not applied, builds will fail.

chapter02/src/test/scala/sofp/unit/Exercises_2_1_7.scala

@@ -0,0 +1,22 @@
+package sofp.unit
+
+import com.eed3si9n.expecty.Expecty.expect
+import munit.FunSuite
+
+class Exercises_2_1_7 extends FunSuite {
+
+  test("exercise 2.1.7.1") {
+
+    val allPairs      =
+      (0 to 9).flatMap { i =>
+        (0 to 9).map { j =>
+          (i, j)
+        }
+      }
+    val filteredPairs = allPairs.filter { case (i, j) => i + 4 * j > i * j }
+
+    expect(filteredPairs.take(4) == Seq((0, 1), (0, 2), (0, 3), (0, 4)))
+    expect(filteredPairs.length == 64)
+  }
+
+}