Boundary Value Analysis

Runs in browser Test Design

A detailed BVA worksheet: define partitions, choose 2-value or 3-value BVA, and get a test table with expected pass/fail for every boundary.

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What are black-box test design techniques?

Black-box techniques derive test cases from the specification without reading the code: equivalence partitioning groups inputs that should behave the same, boundary value analysis tests the edges of each group (0, 1, max, max+1), decision tables enumerate combinations of conditions, state transition testing walks the allowed and forbidden state changes, and pairwise testing covers every pair of parameter values with far fewer cases than the full product.

Read the guide: How to Write Test Cases

How to use Boundary Value Analysis

  1. Define the partitions as fields with min= and max= limits.
  2. Select 2-value or 3-value BVA.
  3. Analyze to get the worksheet, the summary counts and the test cases.

Boundary Value Analysis features

  • Worksheet combining equivalence classes with every boundary per field
  • 2-value or 3-value BVA as defined in the ISTQB Foundation syllabus, plus one nominal mid-range value as a valid control value (not an ISTQB boundary)
  • Expected pass/fail per boundary and numbered test cases
  • Handles integers, decimals, string lengths, list sizes, file sizes and date ranges
  • Export as Markdown, JSON, CSV or Gherkin

Boundary Value Analysis example

Worksheet for a quantity field

Input:

quantity: integer, min=1, max=10

Output:

quantity  Below minimum (min − 1)   0    Fail (rejected)
quantity  Minimum (min)             1    Pass (accepted)
quantity  Just above minimum        2    Pass (accepted)
quantity  Nominal (mid-range)       6    Pass (accepted)
quantity  Just below maximum        9    Pass (accepted)
quantity  Maximum (max)             10   Pass (accepted)
quantity  Above maximum (max + 1)   11   Fail (rejected)
For quantity 1–10, 2-value BVA tests 0, 1, 10 and 11; 3-value BVA adds the valid neighbours 2 and 9 just inside each edge.

quantity: integer, min=1, max=10

Axis from 0 to 11
  • < 1Invalid: below minimum
  • 1–10Valid range
  • > 10Invalid: above maximum
  1. 10 min − 1Expected fail (rejected)
  2. 21 minExpected pass (accepted)
  3. 32 min + 13-value BVA only · expected pass (accepted)
  4. 46 NominalValid control value, not a boundary
  5. 59 max − 13-value BVA only · expected pass (accepted)
  6. 610 maxExpected pass (accepted)
  7. 711 max + 1Expected fail (rejected)

Computed by the tool for this example. Both modes also test the nominal value 6.

Frequently asked questions about Boundary Value Analysis

2-value or 3-value BVA — which should I use?

2-value BVA tests each boundary and its nearest invalid neighbour. 3-value BVA adds the valid neighbour on the inside and catches more off-by-one mistakes; choose it for high-risk inputs. The ISTQB Foundation syllabus presents both variants without making either one the default.

What does the worksheet show?

For each field: the valid and invalid equivalence classes, every boundary, the exact test value and whether it should pass or fail, plus a numbered test case per row. Each ranged field also gets one nominal mid-range value, which is a valid control value rather than a boundary.

Are open ranges handled?

A field with only min or only max gets boundaries on that side; a field with neither gets zero, negative, large and beyond-safe-integer probes.

Can I export the worksheet?

Yes — the worksheet table downloads as CSV, and the test cases export as Markdown, JSON, CSV or Gherkin.

References