Inline snapshots

assertInlineSnapshot controls data defined in your source code.

You can use it to update values, such as case classes or sealed traits.

case class Config(environment: String, region: String)
val found = Config(environment = "dev", region = "us-east-2")

assertInlineSnapshot(found, Config(environment = "prod", region = "us-east-1"))

After running sbt test and snapshot4sPromote, the data will be updated.

case class Config(environment: String, region: String)
val found = Config(environment = "dev", region = "us-east-2")

assertInlineSnapshot(found, Config(environment = "dev", region = "us-east-2"))

You can also use it for strings.

assertInlineSnapshot(found = "The answer", "The answer")

If you have a long string, consider using file snapshots instead.

New snapshots

Use ??? to create a new snapshot:

case class Config(environment: String, region: String)
val found = Config(environment = "dev", region = "us-east-2")

assertInlineSnapshot(found, ???)

Promote your snapshots and see snapshot4s fill in the blanks:

sbt test
sbt snapshot4sPromote

case class Config(environment: String, region: String)
val found = Config(environment = "dev", region = "us-east-2")

assertInlineSnapshot(found, Config(environment = "dev", region = "us-east-2"))

Supported data types

The assertInlineSnapshot assertion will work for products and case classes as well as strings and primitive types.

assertInlineSnapshot(found = 1, 1)
assertInlineSnapshot(found = "The answer", "The answer")

case class Person(name: String)
assertInlineSnapshot(found = Person("Alice"), Person("Alice"))
assertInlineSnapshot(found = Nil, List(Person("Alice"), Person("Bob")))

Unsupported data types

It should not be used on variables.

val personVariable = Person("Bob") 
assertInlineSnapshot(found = Person("Alice"), personVariable) // Bad: personVariable will be replaced with Person("Alice")
assertInlineSnapshot(found = Person("Alice"), Person("Bob"))  // Good: "Bob" will be replaced with "Alice".

It fails to compile for values that can't be represented as source code.

assertInlineSnapshot(found = new Object(), new Object())
// error:
// Cannot derive Repr instance. The type parameter is neither a Sum nor Product type.
// 
// See the guide for a list of supported types:
// https://siriusxm.github.io/snapshot4s/inline-snapshots/#supported-data-types
// assertInlineSnapshot(found = new Object(), new Object())
//                                                        ^