Add extra scopes for BehaviorSpec

To improve BehaviorSpec customizability, this commit adds extra scopes to BehaviorSpec. As discussed, users can concatenate `And` indefinitely, but it's ok. As `And` is optional to complete a test. This behavior is also observed in `FreeSpec`, as it can concatenate infinite test scopes too.

To do that, every context (Given, And/When and Then) receive a new possibility of scoping, `And`. There are some variations of it, to build tests correctly: GivenAndContext, WhenAndContext and ThenAndContext. All of these are optional to use.

Fixes #562

kotlintest-core/src/main/kotlin/io/kotlintest/specs/AbstractBehaviorSpec.kt

@@ -15,48 +15,156 @@ abstract class AbstractBehaviorSpec(body: AbstractBehaviorSpec.() -> Unit = {})
     body()
   }
 
+  fun Given(name: String, test: suspend GivenContext.() -> Unit) = addGivenContext(name, test)
+  fun given(name: String, test: suspend GivenContext.() -> Unit) = addGivenContext(name, test)
+
+  private fun addGivenContext(name: String, test: suspend GivenContext.() -> Unit) {
+    addTestCase("Given: $name", { thisSpec.GivenContext(this).test() }, defaultTestCaseConfig, TestType.Container)
+  }
+
   @KotlinTestDsl
   inner class GivenContext(val context: TestContext) {
-    suspend fun And(name: String, test: suspend WhenContext.() -> Unit) = and(name, test)
-    suspend fun and(name: String, test: suspend WhenContext.() -> Unit) = add("And: $name", test)
-    suspend fun When(name: String, test: suspend WhenContext.() -> Unit) = `when`(name, test)
-    suspend fun `when`(name: String, test: suspend WhenContext.() -> Unit) = add("When: $name", test)
-    private suspend fun add(name: String, test: suspend WhenContext.() -> Unit) =
-        context.registerTestCase(name, this@AbstractBehaviorSpec, { this@AbstractBehaviorSpec.WhenContext(this).test() }, this@AbstractBehaviorSpec.defaultTestCaseConfig, TestType.Container)
+    suspend fun And(name: String, test: suspend GivenAndContext.() -> Unit) = addAndContext(name, test)
+    suspend fun and(name: String, test: suspend GivenAndContext.() -> Unit) = addAndContext(name, test)
+
+    private suspend fun addAndContext(name: String, test: suspend GivenAndContext.() -> Unit) {
+      context.registerTestCase("And: $name", thisSpec, { thisSpec.GivenAndContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    suspend fun When(name: String, test: suspend WhenContext.() -> Unit) = addWhenContext(name, test)
+    suspend fun `when`(name: String, test: suspend WhenContext.() -> Unit) = addWhenContext(name, test)
+
+    private suspend fun addWhenContext(name: String, test: suspend WhenContext.() -> Unit) {
+      context.registerTestCase("When: $name", thisSpec, { thisSpec.WhenContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    suspend fun Then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+    suspend fun then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+
+    private suspend fun addThenContext(name: String, test: suspend ThenContext.() -> Unit) {
+      context.registerTestCase("Then: $name", thisSpec, { thisSpec.ThenContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    fun then(name: String) = TestScope(name, context)
+  }
+
+  @KotlinTestDsl
+  inner class GivenAndContext(val context: TestContext) {
+    suspend fun And(name: String, test: suspend GivenAndContext.() -> Unit) = addAndContext(name, test)
+    suspend fun and(name: String, test: suspend GivenAndContext.() -> Unit) = addAndContext(name, test)
+
+    private suspend fun addAndContext(name: String, test: suspend GivenAndContext.() -> Unit) {
+      context.registerTestCase("And: $name", thisSpec, { thisSpec.GivenAndContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    suspend fun When(name: String, test: suspend WhenContext.() -> Unit) = addWhenContext(name, test)
+    suspend fun `when`(name: String, test: suspend WhenContext.() -> Unit) = addWhenContext(name, test)
+
+    private suspend fun addWhenContext(name: String, test: suspend WhenContext.() -> Unit) {
+      context.registerTestCase("When: $name", thisSpec, { thisSpec.WhenContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    suspend fun Then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+    suspend fun then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+
+    private suspend fun addThenContext(name: String, test: suspend ThenContext.() -> Unit) {
+      context.registerTestCase("Then: $name", thisSpec, { thisSpec.ThenContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    fun then(name: String) = TestScope(name, context)
   }
 
   @KotlinTestDsl
   inner class WhenContext(val context: TestContext) {
-    suspend fun Then(name: String, test: suspend TestContext.() -> Unit) = then(name, test)
-    suspend fun then(name: String, test: suspend TestContext.() -> Unit) =
-        context.registerTestCase("Then: $name", this@AbstractBehaviorSpec, test, this@AbstractBehaviorSpec.defaultTestCaseConfig, TestType.Test)
+    suspend fun And(name: String, test: suspend WhenAndContext.() -> Unit) = addAndContext(name, test)
+    suspend fun and(name: String, test: suspend WhenAndContext.() -> Unit) = addAndContext(name, test)
+
+    private suspend fun addAndContext(name: String, test: suspend WhenAndContext.() -> Unit) {
+      context.registerTestCase("And: $name", thisSpec, { thisSpec.WhenAndContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    suspend fun Then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+    suspend fun then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
 
-    fun then(name: String): ThenScope = ThenScope(name, context)
+    private suspend fun addThenContext(name: String, test: suspend ThenContext.() -> Unit) {
+      context.registerTestCase("Then: $name", thisSpec, { thisSpec.ThenContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Test)
+    }
+
+    fun then(name: String) = TestScope(name, context)
+  }
+
+  @KotlinTestDsl
+  inner class WhenAndContext(val context: TestContext) {
+    suspend fun And(name: String, test: suspend WhenAndContext.() -> Unit) = addAndContext(name, test)
+    suspend fun and(name: String, test: suspend WhenAndContext.() -> Unit) = addAndContext(name, test)
+
+    private suspend fun addAndContext(name: String, test: suspend WhenAndContext.() -> Unit) {
+      context.registerTestCase("And: $name", thisSpec, { thisSpec.WhenAndContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Container)
+    }
+
+    suspend fun Then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+    suspend fun then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+
+    private suspend fun addThenContext(name: String, test: suspend ThenContext.() -> Unit) {
+      context.registerTestCase("Then: $name", thisSpec, { thisSpec.ThenContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Test)
+    }
+
+    fun then(name: String) = TestScope(name, context)
   }
 
   @KotlinTestDsl
-  inner class ThenScope(val name: String, val context: TestContext) {
+  inner class ThenContext(val context: TestContext) {
+    suspend fun And(name: String, test: suspend ThenAndContext.() -> Unit) = addAndContext(name, test)
+    suspend fun and(name: String, test: suspend ThenAndContext.() -> Unit) = addAndContext(name, test)
 
+    private suspend fun addAndContext(name: String, test: suspend ThenAndContext.() -> Unit) {
+      context.registerTestCase("And: $name", thisSpec, { thisSpec.ThenAndContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Test)
+    }
+
+  }
+
+  @KotlinTestDsl
+  inner class ThenAndContext(val context: TestContext) {
+    suspend fun And(name: String, test: suspend ThenAndContext.() -> Unit) = addAndContext(name, test)
+    suspend fun and(name: String, test: suspend ThenAndContext.() -> Unit) = addAndContext(name, test)
+
+    private suspend fun addAndContext(name: String, test: suspend ThenAndContext.() -> Unit) {
+      context.registerTestCase("And: $name", thisSpec, { thisSpec.ThenAndContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Test)
+    }
+
+    suspend fun Then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+    suspend fun then(name: String, test: suspend ThenContext.() -> Unit) = addThenContext(name, test)
+
+    private suspend fun addThenContext(name: String, test: suspend ThenContext.() -> Unit) {
+      context.registerTestCase("Then: $name", thisSpec, { thisSpec.ThenContext(this).test() }, thisSpec.defaultTestCaseConfig, TestType.Test)
+    }
+
+    fun then(name: String) = TestScope(name, context)
+  }
+
+  @KotlinTestDsl
+  inner class TestScope(val name: String, val context: TestContext) {
     suspend fun config(
-        invocations: Int? = null,
-        enabled: Boolean? = null,
-        timeout: Duration? = null,
-        threads: Int? = null,
-        tags: Set<Tag>? = null,
-        extensions: List<TestCaseExtension>? = null,
-        test: TestContext.() -> Unit) {
+            invocations: Int? = null,
+            enabled: Boolean? = null,
+            timeout: Duration? = null,
+            threads: Int? = null,
+            tags: Set<Tag>? = null,
+            extensions: List<TestCaseExtension>? = null,
+            test: TestContext.() -> Unit) {
       val config = TestCaseConfig(
-          enabled ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.enabled,
-          invocations ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.invocations,
-          timeout ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.timeout,
-          threads ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.threads,
-          tags ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.tags,
-          extensions ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.extensions)
+              enabled ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.enabled,
+              invocations ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.invocations,
+              timeout ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.timeout,
+              threads ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.threads,
+              tags ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.tags,
+              extensions ?: this@AbstractBehaviorSpec.defaultTestCaseConfig.extensions)
+
       context.registerTestCase(name, this@AbstractBehaviorSpec, { test.invoke(this) }, config, TestType.Test)
     }
   }
 
-  fun Given(name: String, test: suspend GivenContext.() -> Unit) = given(name, test)
-  fun given(name: String, test: suspend GivenContext.() -> Unit) =
-      addTestCase("Given: $name", { this@AbstractBehaviorSpec.GivenContext(this).test() }, defaultTestCaseConfig, TestType.Container)
+  private val thisSpec: AbstractBehaviorSpec
+    get() = this@AbstractBehaviorSpec
+
 }

kotlintest-tests/kotlintest-tests-core/src/test/kotlin/com/sksamuel/kotlintest/specs/behavior/BehaviorSpecTest.kt

@@ -1,12 +1,89 @@
 package com.sksamuel.kotlintest.specs.behavior
 
+import io.kotlintest.Spec
+import io.kotlintest.TestCase
+import io.kotlintest.TestResult
 import io.kotlintest.matchers.numerics.shouldBeLessThan
+import io.kotlintest.matchers.numerics.shouldNotBeLessThan
+import io.kotlintest.matchers.string.shouldStartWith
 import io.kotlintest.shouldBe
 import io.kotlintest.specs.BehaviorSpec
 import java.util.concurrent.atomic.AtomicInteger
 
 class BehaviorSpecTest : BehaviorSpec() {
+
+  private val counter = AtomicInteger(0)
+
   init {
+    Given("The string foo") {
+      val foo = "foo"
+
+      And("The string jar") {
+        val jar = "jar"
+
+        When("I add them together") {
+          val together = foo + jar
+
+          Then("It should be foojar") {
+            together shouldBe "foojar"
+          }
+        }
+      }
+
+      And("The string bar") {
+        val bar = "bar"
+
+        And("The string fuz") {
+          val fuz = "fuz"
+
+          When("I add them together") {
+            val together = foo + bar + fuz
+
+            And("Count their length") {
+              val length = together.length
+
+              And("Sum one to it") {
+                val sum = length + 1
+
+                Then("It should be 10") {
+                  sum shouldBe 10
+                }
+              }
+
+              Then("It should be 9") {
+                length shouldBe 9
+
+                And("It should not be < 0") {
+                  length shouldNotBeLessThan 0
+                }
+              }
+            }
+
+            Then("It should be foobarfuz") {
+              together shouldBe "foobarfuz"
+            }
+
+            And("I make it uppercase") {
+              val upper = together.toUpperCase()
+
+              Then("It should be FOOBARFUZ") {
+                upper shouldBe "FOOBARFUZ"
+              }
+
+              Then("It should start with F") {
+                upper shouldStartWith "F"
+              }
+            }
+          }
+        }
+      }
+
+      Then("It should be foo") {
+        foo shouldBe "foo"
+      }
+    }
+
+
     given("a") {
       `when`("b") {
         then("c") {
@@ -19,5 +96,45 @@ class BehaviorSpecTest : BehaviorSpec() {
         counter.get() shouldBe 3
       }
     }
+
+    given("A") {
+
+      counter.incrementAndGet()
+
+      and("b") {
+
+        counter.incrementAndGet()
+
+        and("c") {
+
+          counter.incrementAndGet()
+
+          `when`("d") {
+
+            counter.incrementAndGet()
+
+            and("e") {
+
+              counter.incrementAndGet()
+
+              then("f") {
+
+                counter.incrementAndGet()
+
+                and("g") {
+
+                  counter.incrementAndGet()
+
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  override fun afterSpecClass(spec: Spec, results: Map<TestCase, TestResult>) {
+    counter.get() shouldBe 7
   }
 }