Inline assertions on facets (#64)

selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/Selfie.kt

@@ -46,33 +46,42 @@ object Selfie {
   }
 
   open class LiteralStringSelfie
-  internal constructor(protected val actual: Snapshot, val onlyFacets: Collection<String>? = null) {
+  internal constructor(
+      protected val actual: Snapshot,
+      private val onlyFacets: Collection<String>? = null
+  ) {
     init {
       if (onlyFacets != null) {
         check(onlyFacets.all { it == "" || actual.facets.containsKey(it) }) {
           "The following facets were not found in the snapshot: ${onlyFacets.filter { actual.subjectOrFacetMaybe(it) == null }}\navailable facets are: ${actual.facets.keys}"
         }
-        check(onlyFacets.size > 1) { "Must have at least one facet to display, this was empty." }
+        check(onlyFacets.isNotEmpty()) {
+          "Must have at least one facet to display, this was empty."
+        }
       }
     }
     /** Extract a single facet from a snapshot in order to do an inline snapshot. */
     fun facet(facet: String) = LiteralStringSelfie(actual, listOf(facet))
     /** Extract a multiple facets from a snapshot in order to do an inline snapshot. */
     fun facets(vararg facets: String) = LiteralStringSelfie(actual, facets.toList())
     private fun actualString(): String {
-      if ((onlyFacets == null && actual.facets.isEmpty()) || actual.facets.size == 1) {
+      if (actual.facets.isEmpty() || onlyFacets?.size == 1) {
         // single value doesn't have to worry about escaping at all
-        val onlyValue =
-            actual.run { if (facets.isEmpty()) subject else facets[onlyFacets!!.first()]!! }
+        val onlyValue = actual.subjectOrFacet(onlyFacets?.first() ?: "")
         return if (onlyValue.isBinary) {
           TODO("BASE64")
         } else onlyValue.valueString()
       } else {
         // multiple values might need our SnapshotFile escaping, we'll use it just in case
+        val facetsToCheck =
+            onlyFacets
+                ?: buildList {
+                  add("")
+                  addAll(actual.facets.keys)
+                }
         val snapshotToWrite =
-            if (onlyFacets == null) actual
-            else Snapshot.ofEntries(onlyFacets.map { entry(it, actual.subjectOrFacet(it)) })
-        return serialize(snapshotToWrite, onlyFacets != null && !onlyFacets.contains(""))
+            Snapshot.ofEntries(facetsToCheck.map { entry(it, actual.subjectOrFacet(it)) })
+        return serializeMultiple(snapshotToWrite, !facetsToCheck.contains(""))
       }
     }
     fun toBe_TODO() = toBeDidntMatch(null, actualString(), LiteralString)
@@ -84,7 +93,9 @@ object Selfie {
   }
 
   @JvmStatic
-  fun <T> expectSelfie(actual: T, camera: Camera<T>) = DiskSelfie(camera.snapshot(actual))
+  fun <T> expectSelfie(actual: T, camera: Camera<T>) = expectSelfie(camera.snapshot(actual))
+
+  @JvmStatic fun expectSelfie(actual: Snapshot) = DiskSelfie(actual)
 
   @JvmStatic fun expectSelfie(actual: String) = DiskSelfie(Snapshot.of(actual))
 
@@ -166,12 +177,12 @@ internal class ExpectedActual(val expected: Snapshot?, val actual: Snapshot) {
       val includeRoot = mismatchInExpected.containsKey("")
       throw AssertionFailedError(
           "Snapshot failure",
-          serialize(Snapshot.ofEntries(mismatchInExpected.entries), !includeRoot),
-          serialize(Snapshot.ofEntries(mismatchInActual.entries), !includeRoot))
+          serializeMultiple(Snapshot.ofEntries(mismatchInExpected.entries), !includeRoot),
+          serializeMultiple(Snapshot.ofEntries(mismatchInActual.entries), !includeRoot))
     }
   }
 }
-private fun serialize(actual: Snapshot, removeEmptySubject: Boolean): String {
+private fun serializeMultiple(actual: Snapshot, removeEmptySubject: Boolean): String {
   if (removeEmptySubject) {
     check(actual.subject.valueString().isEmpty()) {
       "The subject was expected to be empty, was '${actual.subject.valueString()}'"
@@ -181,6 +192,17 @@ private fun serialize(actual: Snapshot, removeEmptySubject: Boolean): String {
   file.snapshots = ArrayMap.of(mutableListOf("" to actual))
   val buf = StringBuilder()
   file.serialize(buf::append)
-  val str = buf.toString()
-  return if (removeEmptySubject) str else str
+
+  check(buf.startsWith(EMPTY_SUBJECT))
+  check(buf.endsWith(EOF))
+  buf.setLength(buf.length - EOF.length)
+  val str = buf.substring(EMPTY_SUBJECT.length)
+  return if (!removeEmptySubject) str
+  else {
+    check(str[0] == '\n')
+    str.substring(1)
+  }
 }
+
+private const val EMPTY_SUBJECT = "╔═  ═╗\n"
+private const val EOF = "\n╔═ [end of file] ═╗\n"

selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/WriteTracker.kt

@@ -101,6 +101,10 @@ internal class DiskWriteTracker : WriteTracker<String, Snapshot>() {
 internal class InlineWriteTracker : WriteTracker<CallLocation, LiteralValue<*>>() {
   fun record(call: CallStack, literalValue: LiteralValue<*>, layout: SnapshotFileLayout) {
     recordInternal(call.location, literalValue, call, layout)
+    if (literalValue.expected != null) {
+      throw UnsupportedOperationException(
+          "`.toBe() didn't match! Change to `toBe_TODO()` to record a new value until https://github.com/diffplug/selfie/pull/49 is merged.")
+    }
   }
   fun hasWrites(): Boolean = writes.isNotEmpty()
 

selfie-runner-junit5/src/test/kotlin/com/diffplug/selfie/junit5/InlineFacetTest.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2023 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.selfie.junit5
+
+import kotlin.test.Test
+
+class InlineFacetTest : Harness("undertest-junit5") {
+  @Test
+  fun readPasses() {
+    gradleReadSS()
+  }
+}

undertest-junit5/src/test/kotlin/undertest/junit5/UT_InlineFacetTest.kt

@@ -0,0 +1,60 @@
+package undertest.junit5
+
+import com.diffplug.selfie.Selfie.expectSelfie
+import com.diffplug.selfie.Snapshot
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+
+class UT_InlineFacetTest {
+  @Test fun singleFacet() {
+    val zero = Snapshot.of("no facets")
+    expectSelfie(zero).toBe("no facets")
+    expectSelfie(zero).facet("").toBe("no facets")
+    expectSelfie(zero).facets("").toBe("no facets")
+    assertThrows<Throwable> { expectSelfie(zero).toBe("WRONG") }
+    assertThrows<Throwable> { expectSelfie(zero).facet("").toBe("WRONG") }
+    assertThrows<Throwable> { expectSelfie(zero).facets("").toBe("WRONG") }
+
+    val one = Snapshot.of("subject").plusFacet("facet", "facetValue")
+    expectSelfie(one).facet("").toBe("subject")
+    expectSelfie(one).facets("").toBe("subject")
+    expectSelfie(one).facet("facet").toBe("facetValue")
+    expectSelfie(one).facets("facet").toBe("facetValue")
+
+    assertThrows<Throwable> { expectSelfie(one).facet("").toBe("WRONG") }
+    assertThrows<Throwable> { expectSelfie(one).facets("").toBe("WRONG") }
+    assertThrows<Throwable> { expectSelfie(one).facet("facet").toBe("WRONG") }
+    assertThrows<Throwable> { expectSelfie(one).facets("facet").toBe("WRONG") }
+  }
+
+  @Test fun multipleFacets() {
+    val multiple =
+        Snapshot.of("subject")
+            .plusFacet("facet1", "facetValue1")
+            .plusFacet("facet2", "facetValue2")
+            .plusFacet("facet3", "facetValue3")
+    expectSelfie(multiple)
+        .toBe(
+            "subject\n" +
+                "╔═ [facet1] ═╗\n" +
+                "facetValue1\n" +
+                "╔═ [facet2] ═╗\n" +
+                "facetValue2\n" +
+                "╔═ [facet3] ═╗\n" +
+                "facetValue3")
+    assertThrows<Throwable> { expectSelfie(multiple).toBe("WRONG") }
+    expectSelfie(multiple)
+        .facets("", "facet1")
+        .toBe("subject\n" + "╔═ [facet1] ═╗\n" + "facetValue1")
+    assertThrows<Throwable> { expectSelfie(multiple).facets("", "facet1").toBe("WRONG") }
+    expectSelfie(multiple)
+        .facets("facet3", "facet2")
+        .toBe("╔═ [facet2] ═╗\n" + "facetValue2\n" + "╔═ [facet3] ═╗\n" + "facetValue3")
+// TODO: order of lenses should matter
+    assertThrows<Throwable> { expectSelfie(multiple).facets("facet3", "facet2").toBe("WRONG") }
+    expectSelfie(multiple)
+        .facets("facet1", "")
+        .toBe("subject\n" + "╔═ [facet1] ═╗\n" + "facetValue1")
+    assertThrows<Throwable> { expectSelfie(multiple).facets("facet1", "").toBe("WRONG") }
+  }
+}