Library for testing Kotlin JSON applications
This library provides a convenient way of testing applications that produce JSON results. It uses a Kotlin DSL to describe the expected JSON values, and produces detailed error messages in the case of failure.
The library is an evolution of the json-kotlin-test project.
This library operates almost identically to the earlier library, and in most cases users will need to change only the
dependency coordinates and an import statement in order to convert to the new library.
One very small change that will affect only those who examine the content of the error messages, is that error locations are now output in JSON Pointer form instead of pseudo-JavaScript. This is to bring the internal references within a JSON array or object into line with the approach taken by JSON Schema.
New in version 2.1: the property, item and value tests may now take any of the java.time classes or
kotlin.time.Duration or UUID as a parameter.
There are often multiple ways of representing these classes in string form (for example, a time may include or omit
trailing zeros on fractional seconds, or a UUID may use upper or lower case alphabetic characters), so using string
comparisons in tests could cause those tests to fail incorrectly.
The new tests should be used in preference to string tests from now on.
New in version 2.2: the property, item and value tests may now take an enum value as a parameter, and the
effect of the test is to do a string comparison on the enum name.
This is just a matter of convenience – the tests are simpler if they don't require a .name or .toString().
New in version 3.0: the integer, localDate etc. named lambda tests are now named isInteger, isLocalDate
etc.
This is for consistency with the newly-added isObject and isArray tests.
Also, the lambda functions have been moved to standalone functions, so they each require an import statement.
New in version 3.9: the anyItem test allows for the checking of array items in an unordered set.
In a test class:
@Test fun `should produce correct JSON name data`() {
val json = functionUnderTest()
// json is (for example):
// {"data":[{"id":1234,"surname":"Walker","givenNames":["Richard"]}]}
expectJSON(json) {
property("data") {
item(0) {
property("id", 1234)
property("surname", "Walker")
property("givenNames") {
count(1)
item(0, "Richard")
}
propertyAbsent("birthDate")
}
}
}
}Many Kotlin applications return their result in the form of a JSON object, or in some cases, as an array of JSON objects. When we attempt to test these applications, we run into a simple problem – there may be many valid JSON representations of the same object. The properties of a JSON object do not have a pre-determined order, and given a valid set of properties, any sequence of those properties is equally valid.
Also, the JSON specification allows for whitespace to be added at many points in the JSON string, without affecting the meaning of the content.
All of this means that it is not possible to test the results of a function returning JSON simply by performing a string comparison on the output. We need a means of checking the data content of the JSON, regardless of the formatting.
Many developers avoid the problem by deserializing the JSON into the internal form of the object for comparison, but that is not always a useful option. And there are libraries that will check an arbitrary JSON string, but they are mostly written in and for Java, and they do not take advantage of the capabilities of Kotlin.
The kjson-test library allows the expected content of a JSON object to be described in a simple, intuitive form,
allowing functions returning JSON to be tested easily.
In many cases, the expected values will be known precisely, and the basic forms of comparison make a good starting point:
property("id", 1234)
property("surname", "Walker")This checks that the current node is an object with a property named "id" having the value 1234, and another property "surname" with the value "Walker".
Nested objects may be checked by:
property("details") {
// tests on the nested object
}And array items can similarly be checked, either as primitive values or as nested objects or arrays.
The kjson-test library makes testing simple cases easy and clear, and at the same time provides functionality to
meet very broad and complex testing requirements.
First, some terminology:
- a JSON object is the form of JSON structure enclosed in curly braces (
{ }) and containing a set of name-value pairs - these pairs are called properties, and each has a property name, and a value which may be a primitive value or a nested object or array
- a JSON array is an ordered collection of values (possibly nested objects or arrays) enclosed in square brackets
(
[ ]) - an array item is a member of an array
- a JSON value is any of the possible JSON data types: a string, a number, a boolean, the value "null" or a nested object or array
A function or service returning a JSON result will usually return an object or an array of objects, but according to the
JSON specification the string representation of any JSON value is a valid JSON string.
The kjson-test library provides facilities for testing all forms of JSON results.
The set of tests on a JSON string is enclosed in a call to the expectJSON function.
This parses the JSON into an internal form and then performs the tests in the supplied lambda.
expectJSON(stringToBeTested) {
// tests...
}Or, from version 4.1 onwards, the following syntax does exactly the same, but fits in better with the shouldXXXX idiom
of the should-test library:
stringToBeTested shouldMatchJSON {
// tests...
}If any of the tests fail, an AssertionError will be thrown with a detailed error message, usually including expected
and actual values.
The message will in most cases be prefixed by the location of the node in error in
JSON Pointer form
The property function declares a test (or a group of tests) to be performed on a property of an object.
There are several forms of the property function; they all take a property name (String) as the first parameter, and
an expected value or a lambda as the second.
Some examples:
property("name", "William")
property("id", 12345678)
property("open", true)
property("details") {
// tests on nested object or array
}The last of these examples above may be made more specific:
propertyIsObject("details") {
// tests on nested object
}
propertyIsArray("list") {
// tests on nested array
}These functions confirm that the property is of the correct type before applying the nested tests.
And if the property is an array, the array size may be checked in the same operation:
propertyIsArray("list", size = 2) {
// tests on nested array
}The item function declares a test (or a group of tests) to be performed on an item of an array.
As with property, there are several forms of the item function, each taking an index (Int) as the first parameter,
and an expected value or a lambda as the second.
Some examples:
item(0, "bear")
item(27, -1)
item(1, true)
item(4) {
// tests on nested object or array
}As with property tests, if the array item is expected to be an object or an array, additional functions are available:
itemIsObject(3) {
// tests on nested object
}
itemIsArray(0) {
// tests on nested array
}
itemIsArray(0, size = 2) {
// tests on nested array
}In the case of a JSON array representing an unordered set, the anyItem function tests whether any item in
an array matches the specified test.
For example, an authorisation function may return a set of permissions, but the order of the entries is immaterial:
property("permissions") {
anyItem("customer:read")
anyItem("product:read")
}(See also the section on Exhaustive Checks below.)
And again, if the array item is expected to be an object or an array, additional functions are available:
anyItemIsObject {
// tests on nested object
}
anyItemIsArray {
// tests on nested array
}
anyItemIsArray(size = 2) {
// tests on nested array
}In rare cases a JSON string consists of a primitive value (string, number, boolean or null).
The value function allows tests to be applied to the single primitive value, and it takes a single
parameter, the expected value or lambda.
Some examples:
value("success")
value(0)
value(false)
value(null)The lambda parameter of the property, item or value tests normally takes the form of a set of tests applied to a
nested object or array, but it can also specify a named lambda, as in the following examples:
property("account", isInteger)
item(0, isString)
property("id", isUUID)
property("created", isOffsetDateTime)These functions test that a property or item meets a particular requirement, without specifying the exact value.
In the above tests, the property "account" is checked to have an integer value, item 0 of an array contains a string,
property "id" contains a string formatted as a UUID and property "created" contains a string following the pattern of
the OffsetDateTime class.
See the Reference section for a full list of these General Test Lambdas.
Floating point numbers are those with a decimal point, or using the scientific notation (e.g. 1.5e20).
Many decimal floating point numbers can not be represented with complete accuracy in a binary floating point system, so
the kjson-test library converts all such numbers to BigDecimal.
This means that tests on floating point numbers must use BigDecimal, or ClosedRange<BigDecimal>, or
Collection<BigDecimal>.
If a comparison using a BigDecimal is performed against an Int or a Long, the value will be “widened”
to BigDecimal before the test is performed.
One unusual feature of the BigDecimal class is that the equals comparison requires that both the value and the scale
of the number must be equal, but this library uses compareTo to compare the values regardless of scale.
If it is important to confirm that a certain number of decimal digits are present (for example, in a money value), the
scale function may be used to test the number of digits after the decimal point.
An Int or a Long will always be considered as having zero decimal places.
This library looks only at the input JSON, and does not take into account any custom deserializations that may be
applied to the JSON when it is used in other situations.
Custom name annotations, and even the conversion of dates from strings to LocalDate (for example) are not applied.
Checking a value for null, e.g. property("note", null) will check that the named property is present in the JSON
string and has the value null.
Also, for convenience, a named lambda isNull will do the same thing.
In some cases, the fact that a property is not present in the JSON may be taken as being equivalent to the property
being present with a null value.
If it is important to distinguish between a null property and an omitted property, there are functions which test
specifically for the presence or absence of a property:
| To test that a property... | Use |
|---|---|
| ...is present and is not null | property("name", isNonNull) |
| ...is present and is null | property("name", isNull) |
| ...is present whether null or not | propertyPresent("name") |
| ...is not present | propertyAbsent("name") |
| ...is not present, or is present and is null | propertyAbsentOrNull("name") |
Instead of checking all of the properties that are expected not to be present, it may often be simpler to use the
count function to check the number of properties that are present.
You can check a value as being a member of a Collection.
For example:
property("quality", setOf("good", "bad"))This test will succeed if the value of the property is one of the members of the set.
The Collection must be of the appropriate type for the value being checked, and each of the functions property,
item and value has an overloaded version that takes a Collection.
You can also check a value as being included in a range (IntRange, LongRange or ClosedRange).
For example:
property("number", 1000..9999)As with Collection, the range must be of the appropriate type, and each of the functions property, item and
value has an overloaded version that takes a range.
The length function is available to check the length of a string.
If, for example, you expect a string to contain between 5 and 20 characters, but you don't need to check the exact
contents, you can specify:
property("name", length(5..20))The length may be specified as an integer value or an IntRange.
It is also possible to check a string against a Regex, for example:
property("name", Regex("^[A-Za-z]+$"))To confirm that all properties of an object or all items in an array are tested, the tests may be enclosed in an
exhaustive block, for example:
property("address") {
exhaustive {
property("number", 27)
property("streetName", "23rd")
property("streetType", "St")
}
}This will cause an error to be reported if the object contains other properties in addition to those tested.
An exhaustive block can also check that all items in an array have been tested.
This can be particularly useful when paired with the anyItem test, for example:
property("members") {
exhaustive {
anyItem("Tom")
anyItem("Dick")
anyItem("Harry")
}
}This tests that the array at members contains the items "Tom", "Dick" and "Harry" in any order, and no other
entries.
You can also check for a value matching one of a number of possibilities.
The oneOf function takes any number of lambdas (as vararg parameters) and executes them in turn until it
finds one that matches.
property("elapsedTime") {
oneOf(isDuration, isInteger)
}To simplify the use of lambdas in the oneOf list, the test function creates a lambda representing any of
the available types of test:
property("response") {
oneOf(test(null), test(setOf("YES", "NO")))
}Of course, the full lambda syntax can be used to describe complex combinations.
In the following case, the JSON string may be either {"data":27} or {"error":nnn}, where nnn is a number between
0 and 999.
expectJSON(json) {
oneOf({
property("data", 27)
},{
property("error", 0..999)
})
}In any of the tests that take a lambda parameter, the lambda is not restricted to the functions provided by the library; the full power of Kotlin is available to create tests of any complexity.
The "receiver" for the lambda is an object describing the current node in the JSON structure, and the value is available
as a val named node.
The type of node is Any?, but in practice it will be one of:
StringIntLongBigDecimalBooleanList<Any?>Map<String, Any?>null
(In the case of Map or List, the type parameter Any? will itself be one of the above.)
There are also conversion functions, each of which takes the form of a val with a custom accessor.
These accessors either return the node in the form requested, or throw an AssertionError with a detailed error
message.
| Accessor | Type |
|---|---|
nodeAsString |
String |
nodeAsInt |
Int |
nodeAsLong |
Long |
nodeAsDecimal |
BigDecimal |
nodeAsBoolean |
Boolean |
nodeAsArray |
List<*> |
nodeAsObject |
Map<*, *> |
To report errors, the error function will create an AssertionError with the message provided, prepending
the JSON pointer location for the current node in the JSON.
The showNode function can be used to display the actual node value in the error message.
Example:
expectJSON(jsonString) {
property("abc") {
if (nodeAsInt.rem(3) != 0)
error("Value not divisible by 3 - ${showNode()}")
}
}Many users will wish to use kjson-test in conjunction with the
Spring Framework.
A suggestion for simplifying some forms of Spring testing is included in the Spring and kjson-test guide.
Perhaps the most complex part of kjson-test is the import statement:
import io.kjson.test.JSONExpect.Companion.expectJSONIf the IDE is configured to include the kjson-test library, it will often include the import automatically when you
enter the name of the test function.
From version 4.1 onwards the shouldMatchJSON infix function offers a more attractive syntax, as well as a simpler
import:
import io.kjson.test.shouldMatchJSONThe expectJSON function introduces the set of tests to be performed on the JSON.
It takes two parameters:
- a
Stringcontaining the JSON to be examined - a lambda, specifying the tests to be performed on the JSON
Example:
expectJSON(stringOfJSON) {
property("data") {
// tests ...
}
}The shouldMatchJSON infix function does exactly the same as expectJSON, but uses the more attractive shouldXXXX
syntax.
The LHS argument is the String containing the JSON to be examined, while the RHS is the lambda containing the tests.
Example:
stringOfJSON shouldMatchJSON {
property("data") {
// tests ...
}
}Tests the value of a property of an object. In all cases, the first parameter is the name of the property; the second parameter varies according to the test being performed.
| Signature | Check that the property... |
|---|---|
property(String, String?) |
...is equal to a String or null |
property(String, Int) |
...is equal to an Int |
property(String, Long) |
...is equal to a Long |
property(String, BigDecimal) |
...is equal to a BigDecimal |
property(String, Boolean) |
...is equal to a Boolean |
property(String, Regex) |
...is a String matching the given Regex |
property(String, LocalDate) |
...is a String matching the given LocalDate |
property(String, LocalDateTime) |
...is a String matching the given LocalDateTime |
property(String, LocalTime) |
...is a String matching the given LocalTime |
property(String, OffsetDateTime) |
...is a String matching the given OffsetDateTime |
property(String, OffsetTime) |
...is a String matching the given OffsetTime |
property(String, ZonedDateTime) |
...is a String matching the given ZonedDateTime |
property(String, YearMonth) |
...is a String matching the given YearMonth |
property(String, MonthDay) |
...is a String matching the given MonthDay |
property(String, Year) |
...is a String matching the given Year |
property(String, java.time.Duration) |
...is a String matching the given java.time.Duration |
property(String, Period) |
...is a String matching the given Period |
property(String, kotlin.time.Duration) |
...is a String matching the given kotlin.time.Duration |
property(String, UUID) |
...is a String matching the given UUID |
property(String, Enum<*>) |
...is a String matching the given Enum member |
property(String, IntRange) |
...is in a given range |
property(String, LongRange) |
...is in a given range |
property(String, ClosedRange<*>) |
...is in a given range |
property(String, Collection<*>) |
...is in a given collection |
property(String, JSONExpect.() -> Unit) |
...satisfies the given lambda |
In the case of a ClosedRange or Collection, the parameter type must be Int, Long, BigDecimal or String,
although in practice a range of Int or Long would be more likely to use IntRange or LongRange respectively.
Only the test for String has a signature that allows null values; this is to avoid compile-time ambiguity on tests
against null.
This does not mean that only String properties can be tested for null - a null property in the JSON is typeless
so a test for null would work, regardless of the type that the property would otherwise hold.
One important consideration to keep in mind when using the comparisons involving standard Java classes such as UUID
and LocalDate – some mocking libraries allow the static functions of Java classes to be mocked; for example,
MockK has a function mockkStatic() which will intercept calls to the static functions of a
nominated class.
This type of interception, when used on the standard library classes, can cause comparisons involving those classes to
fail in unpredictable ways, and this technique should probably be avoided when using kjson-test.
The last function signature in the list is the one that specifies a lambda – as is usual in Kotlin, when the last
parameter is a lambda it is usually written outside the parentheses of the function call.
This is the pattern followed when the lambda is an inline set of tests to be applied to the property, but this function
signature is also used for the general test lambdas, or the length or
scale functions.
Examples:
property("id", 12345)
property("name", "William")
property("dob", LocalDate.of(1996, 7, 4))
property("count", 0..9999)
property("amount", isDecimal)
property("reference", isUUID)
property("address", length(1..80))
property("code", setOf("AAA", "PQR", "XYZ"))
property("details") {
// nested tests
}Tests a property of an object as a nested object. The first parameter is the name of the property in the outer object; the second is an optional lambda of tests to be applied to the nested object.
Examples:
propertyIsObject("address") {
// tests on address object
}
propertyIsObject("details") // no tests on content, just confirm that it is an objectTests a property of an object as an array.
Two forms are available: one which takes the name of the array property, and an optional lambda of tests to be applied
to it, and a second which includes a size parameter to check the size of the array.
Examples:
propertyIsArray("lines") {
// tests on lines array
}
propertyIsArray("details") // no tests on content, just confirm that it is an array
propertyIsArray("lines", size = 4) {
// tests on lines array, after checking that there are 4 items in the array
}Tests the value of an array item. In all cases, the first parameter is the index of the array item (must be non-negative). The second parameter varies according to the test being performed.
| Signature | Check that the array item... |
|---|---|
item(Int, String?) |
...is equal to a String or null |
item(Int, Int) |
...is equal to an Int |
item(Int, Long) |
...is equal to a Long |
item(Int, BigDecimal) |
...is equal to a BigDecimal |
item(Int, Boolean) |
...is equal to a Boolean |
item(Int, Regex) |
...is a String matching the given Regex |
item(Int, LocalDate) |
...is a String matching the given LocalDate |
item(Int, LocalDateTime) |
...is a String matching the given LocalDateTime |
item(Int, LocalTime) |
...is a String matching the given LocalTime |
item(Int, OffsetDateTime) |
...is a String matching the given OffsetDateTime |
item(Int, OffsetTime) |
...is a String matching the given OffsetTime |
item(Int, ZonedDateTime) |
...is a String matching the given ZonedDateTime |
item(Int, YearMonth) |
...is a String matching the given YearMonth |
item(Int, MonthDay) |
...is a String matching the given MonthDay |
item(Int, Year) |
...is a String matching the given Year |
item(Int, java.time.Duration) |
...is a String matching the given java.time.Duration |
item(Int, Period) |
...is a String matching the given Period |
item(Int, kotlin.time.Duration) |
...is a String matching the given kotlin.time.Duration |
item(Int, UUID) |
...is a String matching the given UUID |
item(Int, Enum<*>) |
...is a String matching the given Enum member |
item(Int, IntRange) |
...is in a given range |
item(Int, LongRange) |
...is in a given range |
item(Int, ClosedRange<*>) |
...is in a given range |
item(Int, Collection<*>) |
...is in a given collection |
item(Int, JSONExpect.() -> Unit) |
...satisfies the given lambda |
The notes following property describing the options for the second parameter apply equally to item.
Examples:
item(0, 22)
item(5, "William")
item(4, 2.hours)
item(7, isDecimal)
item(7, scale(0..2))
item(1, isUUID)
item(0) {
// nested tests
}Tests an array item as an object. The first parameter is the index of the array item; the second is an optional lambda of tests to be applied to the object.
Examples:
itemIsObject(0) {
// tests on object
}
itemIsObject(1) // no tests on content, just confirm that it is an objectTests an array item as a nested array.
Two forms are available: one which takes the index of the array item, and an optional lambda of tests to be applied
to it, and a second which includes a size parameter to check the size of the nested array.
Examples:
itemIsArray(0) {
// tests on nested array
}
itemIsArray(2) // no tests on content, just confirm that it is an array
itemIsArray(5, size = 2) {
// tests on nested array, after checking that there are 2 items in the array
}Tests whether an array contains an item matching one or more tests. The parameter varies according to the test being performed.
| Signature | Check that an array item... |
|---|---|
anyItem(String?) |
...is equal to a String or null |
anyItem(Int) |
...is equal to an Int |
anyItem(Long) |
...is equal to a Long |
anyItem(BigDecimal) |
...is equal to a BigDecimal |
anyItem(Boolean) |
...is equal to a Boolean |
anyItem(Regex) |
...is a String matching the given Regex |
anyItem(LocalDate) |
...is a String matching the given LocalDate |
anyItem(LocalDateTime) |
...is a String matching the given LocalDateTime |
anyItem(LocalTime) |
...is a String matching the given LocalTime |
anyItem(OffsetDateTime) |
...is a String matching the given OffsetDateTime |
anyItem(OffsetTime) |
...is a String matching the given OffsetTime |
anyItem(ZonedDateTime) |
...is a String matching the given ZonedDateTime |
anyItem(YearMonth) |
...is a String matching the given YearMonth |
anyItem(MonthDay) |
...is a String matching the given MonthDay |
anyItem(Year) |
...is a String matching the given Year |
anyItem(java.time.Duration) |
...is a String matching the given java.time.Duration |
anyItem(Period) |
...is a String matching the given Period |
anyItem(kotlin.time.Duration) |
...is a String matching the given kotlin.time.Duration |
anyItem(UUID) |
...is a String matching the given UUID |
anyItem(Enum<*>) |
...is a String matching the given Enum member |
anyItem(IntRange) |
...is in a given range |
anyItem(LongRange) |
...is in a given range |
anyItem(ClosedRange<*>) |
...is in a given range |
anyItem(Collection<*>) |
...is in a given collection |
anyItem(JSONExpect.() -> Unit) |
...satisfies the given lambda |
The notes following property describing the options for the second parameter apply equally to anyItem.
Examples:
anyItem(22)
anyItem("William")
anyItem(2.hours)
anyItem(isDecimal)
anyItem(scale(0..2))
anyItem(isUUID)
anyItem {
// nested tests
}Tests whether an array contains an item which is an object, optionally matching a set of tests. The parameter is an optional lambda of tests to be applied to the object.
Examples:
anyItemIsObject {
// tests on object
}
anyItemIsObject() // no tests on content, just confirm that any item is an objectTests whether an array contains an item which is a nested array, optionally matching a set of tests, and also optionally
checking the array size.
Two forms are available: one which takes an optional lambda of tests to be applied to it, and a second which includes a
size parameter to check the size of the nested array.
Examples:
anyItemIsArray {
// tests on nested array
}
anyItemIsArray() // no tests on content, just confirm that any item is a nested array
anyItemIsArray(size = 2) {
// tests on nested array, after checking that there are 2 items in the array
}This function takes one parameter, which varies according to the test being performed.
| Signature | Check that the value... |
|---|---|
value(String?) |
...is equal to a String or null |
value(Int) |
...is equal to an Int |
value(Long) |
...is equal to a Long |
value(BigDecimal) |
...is equal to a BigDecimal |
value(Boolean) |
...is equal to a Boolean |
value(Regex) |
...is a String matching the given Regex |
value(LocalDate) |
...is a String matching the given LocalDate |
value(LocalDateTime) |
...is a String matching the given LocalDateTime |
value(LocalTime) |
...is a String matching the given LocalTime |
value(OffsetDateTime) |
...is a String matching the given OffsetDateTime |
value(OffsetTime) |
...is a String matching the given OffsetTime |
value(ZonedDateTime) |
...is a String matching the given ZonedDateTime |
value(YearMonth) |
...is a String matching the given YearMonth |
value(MonthDay) |
...is a String matching the given MonthDay |
value(Year) |
...is a String matching the given Year |
value(java.time.Duration) |
...is a String matching the given java.time.Duration |
value(Period) |
...is a String matching the given Period |
value(kotlin.time.Duration) |
...is a String matching the given kotlin.time.Duration |
value(UUID) |
...is a String matching the given UUID |
value(Enum<*>) |
...is a String matching the given Enum member |
value(IntRange) |
...is in a given range |
value(LongRange) |
...is in a given range |
value(ClosedRange<*>) |
...is in a given range |
value(Collection<*>) |
...is in a given collection |
value(JSONExpect.() -> Unit) |
...satisfies the given lambda |
The notes following property describing the options for the second parameter apply equally to the sole
parameter of value.
Examples:
value(0..9999)
value(isDecimal)
value(scale(0..2))
value(isLocalDate)Tests the value as an object. The parameter is an optional lambda of tests to be applied to the object.
Examples:
valueIsObject {
// tests on object
}
valueIsObject() // no tests on content, just confirm that it is an objectIt is not usually necessary to perform this test; the first access to a property will raise an exception if the value is not an object.
Tests the value as an array.
Two forms are available: one which takes an optional lambda of tests to be applied to it, and a second which includes a
size parameter to check the size of the array.
Examples:
valueIsArray {
// tests on array
}
valueIsArray() // no tests on content, just confirm that it is an array
valueIsArray(size = 2) {
// tests on array, after checking that there are 2 items in the array
}It is not usually necessary to perform this test; the first access to an array item will raise an exception if the value is not an array.
This is used to check the length of a String property, array item or value.
The parameter may be an Int or an IntRange.
Examples:
property("name", length(1..40))
item(0, length(12))The scale of a BigDecimal may be checked, if it is required that a decimal number have a specific scale.
If the number is parsed as an Int or a Long, the scale will be zero.
The parameter may be an Int or an IntRange.
Examples:
property("amount", scale(1..2))
item(0, scale(0))Tests the count of properties or array items (the length of the array).
The parameter may be an Int or an IntRange.
Examples:
property("options") {
count(2)
item(0, "A")
item(1, "B")
}Test each of the parameters in turn, exiting when one of them matches the node successfully.
It takes a variable number of parameters, each of which is a lambda (the test function may be used to create
lambdas for this purpose).
Examples:
property("id") {
oneOf(isInteger, isUUID)
}
property("result") {
oneof(test(0..99999), test("ERROR"))
}Creates a lambda, principally for use with the oneOf function.
It takes one parameter, which varies according to the type of test.
| Signature | Create a test for... |
|---|---|
test(String?) |
...value equal to a String or null |
test(Int) |
...value equal to an Int |
test(Long) |
...value equal to a Long |
test(BigDecimal) |
...value equal to a BigDecimal |
test(Boolean) |
...value equal to a Boolean |
test(Regex) |
...value a String matching the given Regex |
test(LocalDate) |
...value a String matching the given LocalDate |
test(LocalDateTime) |
...value a String matching the given LocalDateTime |
test(LocalTime) |
...value a String matching the given LocalTime |
test(OffsetDateTime) |
...value a String matching the given OffsetDateTime |
test(OffsetTime) |
...value a String matching the given OffsetTime |
test(ZonedDateTime) |
...value a String matching the given ZonedDateTime |
test(YearMonth) |
...value a String matching the given YearMonth |
test(MonthDay) |
...value a String matching the given MonthDay |
test(Year) |
...value a String matching the given Year |
test(java.time.Duration) |
...value a String matching the given java.time.Duration |
test(Period) |
...value a String matching the given Period |
test(kotlin.time.Duration) |
...value a String matching the given kotlin.time.Duration |
test(UUID) |
...value a String matching the given UUID |
test(Enum<*>) |
...value a String matching the given Enum member |
test(IntRange) |
...value in a given range |
test(LongRange) |
...value in a given range |
test(ClosedRange<*>) |
...value in a given range |
test(Collection<*>) |
...value in a given collection |
The notes following property describing the options for the second parameter apply equally to the sole
parameter of test.
For examples see the oneOf function.
Tests that no property with the specified name is present in the object.
It takes one parameter - the property name (String).
Examples:
property("controls") {
property("openingDate", isLocalDate)
propertyAbsent("closingDate")
}Tests that no property with the specified name is present in the object, or if one is present, that it is null.
It takes one parameter - the property name (String).
Examples:
property("controls") {
property("openingDate", isLocalDate)
propertyAbsentOrNull("closingDate")
}Tests that a property with the specified name is present in the object, regardless of the value.
It takes one parameter - the property name (String).
Examples:
property("book") {
propertyPresent("author")
}In custom tests the current node can be accessed by one of the following:
val name |
Type | Notes |
|---|---|---|
node |
Any? |
|
nodeAsString |
String |
|
nodeAsInt |
Int |
|
nodeAsLong |
Long |
An Int will be accepted and returned as a Long |
nodeAsDecimal |
BigDecimal |
An Int or a Long will be accepted and returned as a BigDecimal |
nodeAsBoolean |
Boolean |
|
nodeAsObject |
Map<*, *> |
|
nodeAsArray |
List<*> |
If the node as not of the required type, an AssertionError will be thrown.
In custom tests the error function will output the message given, prepended with the JSON pointer location for the
current node.
It takes one parameter - the message (String).
The showNode function may be used to format the node for inclusion in an error message.
It takes no parameters.
These are all functions with the signature JSONExpect.() -> Unit, and they may be used with the form of the
property, item or value functions that takes a lambda parameter.
They are useful when only the general nature of the value is to be tested, and the actual value is not important.
| Name | Tests that the value is... |
|---|---|
isNull |
...null |
isNonNull |
...non-null |
isObject |
...an object |
isEmptyObject |
...an empty object (an object with no properties) |
isNonEmptyObject |
...a non-empty object (an object with at least one property) |
isArray |
...an array |
isEmptyArray |
...an empty array |
isNonEmptyArray |
...a non-empty array |
isString |
...a String |
isInteger |
...an Int |
isLongInteger |
...a Long (see 1 below) |
isDecimal |
...a BigDecimal (a number with an optional decimal fraction – see 1 below) |
isUUID |
...a String containing a valid UUID (see 2 below) |
isLocalDate |
...a String containing a valid LocalDate |
isLocalDateTime |
...a String containing a valid LocalDateTime |
isLocalTime |
...a String containing a valid LocalTime |
isOffsetDateTime |
...a String containing a valid OffsetDateTime |
isOffsetTime |
...a String containing a valid OffsetTime |
isZonedDateTime |
...a String containing a valid ZonedDateTime |
isYear |
...a String containing a valid Year |
isYearMonth |
...a String containing a valid YearMonth |
isMonthDay |
...a String containing a valid MonthDay |
isJavaDuration |
...a String containing a valid java.time.Duration |
isPeriod |
...a String containing a valid Period |
isDuration |
...a String containing a valid kotlin.time.Duration |
1 Consistent with the widening of numbers in the tests against Long and BigDecimal values, the
isLongInteger test passes if the value is Int or Long, and the isDecimal test passes if the value is Int or
Long or BigDecimal.
2 The Java UUID.fromString() function does not check that a UUID is valid – it allows the five blocks
of hexadecimal digits to be shorter or longer than their expected lengths (8-4-4-4-12).
The isUUID test performs a strict check of the lengths of the five blocks, as well as the content.
The latest version of the library is 4.1, and it may be obtained from the Maven Central repository. (The following dependency declarations assume that the library will be included for test purposes; this is expected to be its principal use.)
<dependency>
<groupId>io.kjson</groupId>
<artifactId>kjson-test</artifactId>
<version>4.1</version>
<scope>test</scope>
</dependency> testImplementation 'io.kjson:kjson-test:4.1' testImplementation("io.kjson:kjson-test:4.1")Peter Wall
2024-12-19