Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/qala-io/datagen
Java lib that generates random data (numbers, strings, dates) - mostly to facilitate Randomized Testing.
https://github.com/qala-io/datagen
java random random-data-generation random-generation random-number-generators randomization testing
Last synced: 3 months ago
JSON representation
Java lib that generates random data (numbers, strings, dates) - mostly to facilitate Randomized Testing.
- Host: GitHub
- URL: https://github.com/qala-io/datagen
- Owner: qala-io
- License: apache-2.0
- Created: 2016-05-07T20:11:51.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2023-11-29T22:50:17.000Z (about 1 year ago)
- Last Synced: 2023-11-29T23:35:25.599Z (about 1 year ago)
- Topics: java, random, random-data-generation, random-generation, random-number-generators, randomization, testing
- Language: Java
- Homepage: http://qala.io/blog/randomized-testing.html
- Size: 236 KB
- Stars: 58
- Watchers: 7
- Forks: 4
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.txt
Awesome Lists containing this project
README
Datagen
-------
[](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22io.qala.datagen%22)
Java library to generate random data (numbers, strings, dates) - to facilitate
[Randomized Testing](http://qala.io/blog/randomized-testing.html). Randomization may be used to improve coverage, but
it can also speed up the process of writing & running tests. Some use cases for randomization:
* [Combinatorial Testing](./examples/combinatorial.md) - helps reducing the number of test cases you need
to write and run
* [Fighting with Unique Constraints](./examples/unique-constraints.md) - do you have a test that registers users with
unique username? And the next time you run the test it fails because such user already exists..
* ["Wow, I didn't know about that"](./examples/wow-i-did-not-know-that.md) effect - sometimes randomization
may discover tricky cases that you couldn't think of.
* [Which one to pick?](./examples/which-one-to-pick.md) - often when choosing test data there is no clear winner
of what value to pick. Randomization helps with that and ensures we're not prone to Pesticides Effect.
## Example
```java
import java.time.OffsetDateTime;
import static io.qala.datagen.RandomDate.beforeNow;
import static io.qala.datagen.RandomShortApi.*;
public class Dog {
private String name;
private OffsetDateTime timeOfBirth;
private double weight;
private double height;
public static Dog random() {
Dog dog = new Dog();
dog.name = alphanumeric(1, 100);
dog.timeOfBirth = nullOr(beforeNow().offsetDateTime());
dog.weight = positiveDouble();
dog.height = positiveInteger();
return dog;
}
}
```
## [JUnit5 Integration](./junit5/README.md)
```java
@Alphanumeric(min = 2, max = 29, name = "middle value")
@Alphanumeric(length = 30, name = "max boundary")
@English(max=30)
void eachAnnotationInvokesTheTestOnceAndPassesParameters(String value, String name) {
assertTrue(value.length() >= 1 && value.length() <= 31, "Failed case: " + name);
}
@RandomInt(min = 1, name = "greater than zero")
@RandomInt(max = -1, name = "less than zero")
void zeroInt_isNotPassed(int param, String name) {
assertNotEquals(0, param, "Failed case: " + name);
}
```
## Strings
```java
import static io.qala.datagen.RandomValue.*;
import static io.qala.datagen.StringModifier.Impls.*;
import static io.qala.datagen.RandomShortApi.*;
```
| Flexible API | Short API | Result
|----------------------------------------------------------|----------------------|--------
| `length(10).english()` |`english(10)` | `"DcRZUNPrED"`
| `between(1, 10).alphanumeric()` |`alphanumeric(0, 10)` | `"zG9G"`
| `between(1, 10).numeric()` |`numeric(1, 10)` | `"7167162"`
| `length(5).unicode()` |`unicode(5)` | `"䂞ꂣ뢧䯺婜"`
| `length(5).string("A_ B")` | | `" _B B"`
| `length(10).with(specialSymbol()).english()` | | `"hOzKEV#iWv"`
| `length(10).with(oneOf("_,")).english()` | | `"dwei,cNTfW"`
| `length(5).with(spaces()).numeric()` | | `"874 9 "`
| `length(3).with(spaceLeft()).english()` | | `" mT"`
| `length(4).with(spacesRight(2)).english()` | | `"hF "`
| `length(10).with(prefix("BLAH")).numeric()` | | `"BLAH453677"`
| `between(1, 10).alphanumerics(4)` | | `["cvA", "mTMDj0", "N", ""]`
| | `mixedCase("blah")` | `"bLaH"`
## Nulls & Blanks
| API | Result
|----------------------|------------------------
| `nullOrEmpty()` | `""`, `null`
| `nullOrBlank()` | `""`, `" "`, `null`
| `nullOr(10L)` | `null`, `10L`
| `nullOr("string")` | `null`, `"string"`
| `blankOr("string")` | `""`, `" "`, `null`, `"string"`
## Repeats
```java
import static io.qala.datagen.RandomString.Type.*;
import static io.qala.datagen.RandomValue.*;
import static io.qala.datagen.Repeater.*;
repeat(length(4), NUMERIC).string("-").times(4)`
```
Result: `"9338-8349-6940-7714"`
## Numbers
```java
import static io.qala.datagen.RandomValue.*;
import static io.qala.datagen.RandomShortApi.*;
```
|Flexible API | Short API | Result
|---------------------------------------------------------|----------------------|--------
|`between(0, 100).integer()` | `integer(100)` | `89`
|`between(-100, 100).integer()` | `integer(-100, 100)` | `-19`
| | `positiveInteger()` | `3432145`
| | `Long()` | `7635811362052252913`
| | `negativeDouble()` | `-8.9946257128846746E18`
## Collections/Arrays
```java
import static io.qala.datagen.RandomElements.*;
import static io.qala.datagen.RandomShortApi.*;
```
|Flexible API | Short API | Result
|---------------------------------------------------------|----------------------------------------|--------
|`from("A", "B", "C", "D").sample()` | `sample("A", "B", "C")` | `"C"`
|`from("A", "B", "C", "D").sample(2)` | `sampleMultiple(2, "A", "B", "C")` | `["B", "A"]`
|`from("A", "B").sampleWithReplacement(3)` | | `["A", "A", "B"]`
|`from("A", "B", "C").shuffled()` | `shuffled("A", "B", "C")` | `["C", "A", "B"]`
## Java Date
```java
import static io.qala.datagen.RandomValue.*;
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
between(f.parse("2015-01-01"), f.parse("2016-01-01")).date();
```
Result: `2015-11-30T08:33:20.349`
## Java8 DateTime
```java
// Requires Java8 and qala-datagen-java8types dependency
import static io.qala.datagen.RandomDate.*;
```
API | Result
---------------------------------------------------|--------
`plusMinus100Years().zonedDateTime()` | `1937-09-27T01:16:15.925440485+01:00[Europe/Belgrade]`
`since(yearAgo()).instant()` | `2015-11-30T08:39:28.397051483Z`
`before(now()).instant()` | `-241279778-02-14T16:07:18.061693370Z`
`between(yearsAgo(2), startOfMonth()).localDate()` | `2014-09-30`
## Booleans
```java
import static io.qala.datagen.RandomShortApi.*;
```
API | Result
---------------------------------------------------|--------
`bool()` or `weighedTrue(0.5)` | `false`
`bools(4)` | `[false, true, true, false]`
`nullableBool()` | `Boolean.TRUE`
## Functions (for Java8 lambdas)
```java
import static io.qala.datagen.RandomShortApi.*;
Person person = new Person();
callOneOf(() -> person.firstName = english(5),
() -> person.lastName = english(5));
```
Result: `Person[null, "PDGRq"]`
```java
callNoneOrMore(() -> person.firstName = english(5),
() -> person.lastName = english(5));
```
Result: `Person[null, null]`
```
callOneOrMore(() -> person.firstName = english(5),
() -> person.lastName = english(5));
```
Result: `Person["LjxYh", "UXoBt"]`
## Other
- [Maven Central coordinates](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22io.qala.datagen%22)
- Occasional updates are posted in [Twitter](https://twitter.com/Qala_io)
- [Our blog](http://qala.io/blog.html)
## Special thanks
To keep the lib tiny and get rid of extra dependencies (there are no
transitive dependencies) some of the code was borrowed from these libs:
Commons Lang, Commons Math. Hail to open source!