Implement toBe(LITERAL), not just toBe_TODO()

selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/SourceFile.kt

@@ -36,7 +36,8 @@ class SourceFile(filename: String, content: String) {
    * Represents a section of the sourcecode which is a `.toBe(LITERAL)` call. It might also be
    * `.toBe_TODO()` or ` toBe LITERAL` (infix notation).
    */
-  inner class ToBeLiteral internal constructor(private val slice: Slice) {
+  inner class ToBeLiteral
+  internal constructor(private val slice: Slice, private val valueStart: Int) {
     /**
      * Modifies the parent [SourceFile] to set the value within the `toBe` call, and returns the net
      * change in newline count.
@@ -48,7 +49,7 @@ class SourceFile(filename: String, content: String) {
         throw Error(
             "There is an error in " +
                 literalValue.format::class.simpleName +
-                ", the following value isn't roundtripping.\n" +
+                ", the following value isn't round tripping.\n" +
                 "Please this error and the data below at https://github.com/diffplug/selfie/issues/new\n" +
                 "```\n" +
                 "ORIGINAL\n" +
@@ -73,20 +74,45 @@ class SourceFile(filename: String, content: String) {
      * `toBe_TODO()`.
      */
     fun <T : Any> parseLiteral(literalFormat: LiteralFormat<T>): T {
-      // this won't work, because we need to find the `.toBe` and parens
-      TODO("return literalFormat.parse(slice.toString())")
+      return literalFormat.parse(
+          slice.subSequence(valueStart, slice.length - 1).toString(), language)
     }
   }
   fun parseToBe_TODO(lineOneIndexed: Int): ToBeLiteral {
+    return parseToBeLike(".toBe_TODO(", lineOneIndexed)
+  }
+  fun parseToBe(lineOneIndexed: Int): ToBeLiteral {
+    return parseToBeLike(".toBe(", lineOneIndexed)
+  }
+  private fun parseToBeLike(prefix: String, lineOneIndexed: Int): ToBeLiteral {
     val lineContent = contentSlice.unixLine(lineOneIndexed)
-    val idx = lineContent.indexOf(".toBe_TODO()")
+    val idx = lineContent.indexOf(prefix)
     if (idx == -1) {
       throw AssertionError(
-          "Expected to find `.toBe_TODO()` on line $lineOneIndexed, but there was only `${lineContent}`")
+          "Expected to find `$prefix)` on line $lineOneIndexed, but there was only `${lineContent}`")
     }
-    return ToBeLiteral(lineContent.subSequence(idx, idx + ".toBe_TODO()".length))
-  }
-  fun parseToBe(lineOneIndexed: Int): ToBeLiteral {
-    TODO("More complicated because we have to actually parse the literal")
+    var opened = 0
+    val startIndex = idx + prefix.length
+    var endIndex = -1
+    // TODO: do we need to detect paired parenthesis ( ( ) )?
+    for (i in startIndex ..< lineContent.length) {
+      val ch = lineContent[i]
+      // TODO: handle () inside string literal
+      if (ch == '(') {
+        opened += 1
+      } else if (ch == ')') {
+        if (opened == 0) {
+          endIndex = i
+          break
+        } else {
+          opened -= 1
+        }
+      }
+    }
+    if (endIndex == -1) {
+      throw AssertionError(
+          "Expected to find `$prefix)` on line $lineOneIndexed, but there was only `${lineContent}`")
+    }
+    return ToBeLiteral(lineContent.subSequence(idx, endIndex + 1), prefix.length)
   }
 }

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

@@ -22,6 +22,7 @@ import java.nio.file.Files
 import java.nio.file.Path
 import java.util.stream.Collectors
 import kotlin.io.path.name
+import org.opentest4j.AssertionFailedError
 
 /** Represents the line at which user code called into Selfie. */
 data class CallLocation(val clazz: String, val method: String, val file: String?, val line: Int) :
@@ -100,9 +101,21 @@ 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)
+    // assert that the value passed at runtime matches the value we parse at compile time
+    // because if that assert fails, we've got no business modifying test code
+    val file =
+        layout.sourcecodeForCall(call.location)
+            ?: throw Error("Unable to find source file for ${call.location.ideLink(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.")
+      // if expected == null, it's a `toBe_TODO()`, so there's nothing to check
+      val content = SourceFile(file.name, Files.readString(file))
+      val parsedValue = content.parseToBe(call.location.line).parseLiteral(literalValue.format)
+      if (parsedValue != literalValue.expected) {
+        throw AssertionFailedError(
+            "There is likely a bug in Selfie's literal parsing.",
+            literalValue.expected,
+            parsedValue)
+      }
     }
   }
   fun hasWrites(): Boolean = writes.isNotEmpty()
@@ -141,18 +154,7 @@ internal class InlineWriteTracker : WriteTracker<CallLocation, LiteralValue<*>>(
           if (write.literal.expected == null) {
             content.parseToBe_TODO(line)
           } else {
-            content.parseToBe(line).also {
-              val currentValue = it.parseLiteral(write.literal.format)
-              if (currentValue != write.literal.expected) {
-                // TODO: this shouldn't happen here, it should happen
-                // when the write is recorded so that we can fail eagerly,
-                // exceptions thrown here are easy to miss
-                throw org.opentest4j.AssertionFailedError(
-                    "There is likely a bug in Selfie's literal parsing.",
-                    write.literal.expected,
-                    currentValue)
-              }
-            }
+            content.parseToBe(line)
           }
       deltaLineNumbers += toBe.setLiteralAndGetNewlineDelta(write.literal)
     }

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

@@ -33,9 +33,20 @@ class InlineIntTest : Harness("undertest-junit5") {
   }
 
   @Test @Order(2)
-  fun toBe_write() {
+  fun toBe_writeTODO() {
+    ut_mirror().lineWith("expectSelfie").setContent("    expectSelfie(1234).toBe_TODO()")
+    gradleReadSSFail()
     gradleWriteSS()
     ut_mirror().lineWith("expectSelfie").content() shouldBe "    expectSelfie(1234).toBe(1234)"
     gradleReadSS()
   }
+
+  @Test @Order(3)
+  fun toBe_writeLiteral() {
+    ut_mirror().lineWith("expectSelfie").setContent("    expectSelfie(7777).toBe(1234)")
+    gradleReadSSFail()
+    gradleWriteSS()
+    ut_mirror().lineWith("expectSelfie").content() shouldBe "    expectSelfie(7777).toBe(7777)"
+    gradleReadSS()
+  }
 }

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

@@ -6,6 +6,6 @@ import kotlin.test.Test
 
 class UT_InlineIntTest {
   @Test fun singleInt() {
-    expectSelfie(1234).toBe(1234)
+    expectSelfie(7777).toBe(7777)
   }
 }