Diff Tool Exercises

Exercises Jan 7, 2025 (Jan 10, 2025) Loading...

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diff compares two files, highlighting differences. Here's how diff can work for testers. On that page, you'll find links to several tools that implement and build on diff – you may already have your own preference.

In this exercise, you’ll use any diff tool that seems right to you.

This exercise is more fun in a group. If you’re in a group, please talk about what tool you’d use. Perhaps re-run the exercise with someone else’s tool of choice, or with someone else.

The solutions are below. The tool will do most of the work – give yourself kudos for spotting non-trivial things. Zero kudos if you look at the solutions before trying the exercises.

Exercises Group 1 – XML and JSON

Download the linked files, use them in a tool.

If you’re opening the file in a browser, finding out what an xmlschema is, and reading through it, you’re doing it …differently from how I’d expect you to do it.

Exercise 1.01 (XML)

file 1, file 2

Solution

Exercise 1.01 - Lines Removed

in the schema definition, v2 is missing these lines, location 453 in original

<xs:element name="BkPtyId" type="Max35Text" minOccurs="0" maxOccurs="1"/>
<xs:element name="TaxIdNb" type="Max35Text" minOccurs="0" maxOccurs="1"/>

Exercise 1.02 (XML)

file 1, file 2

Solution

Exercise 1.02 - Lines Added

In the schema definition, v2 has had line 699 duplicated in error

</xs:complexType>

Exercise 1.03 (XML)

file 1, file 2

Solution

Exercise 1.03 - Lines Rearranged

In the schema definintion on lines 224 to 234 of v2, SimpleType DocumentType2Code has been rearranged. Kudos if you recognised that it has been sorted

<xs:enumeration value="CINV"/>
<xs:enumeration value="CMCN"/>
<xs:enumeration value="CNFA"/>
<xs:enumeration value="CREN"/>
<xs:enumeration value="DEBN"/>
<xs:enumeration value="DISP"/>
<xs:enumeration value="DNFA"/>
<xs:enumeration value="HIRI"/>
<xs:enumeration value="MSIN"/>
<xs:enumeration value="SBIN"/>
<xs:enumeration value="SOAC"/>

Exercise 1.04 (XML)

file 1, file 2

Solution

Exercise 1.04 Information Changed On A Single Line

In the schema definition on line 463, the order of attributes has been rearranged. Kudos if you noticed that maxOccurs has changed from 4 to 5

<xs:element name="PrvtId" minOccurs="1" maxOccurs="5" type="PersonIdentification3" />

Exercise 1.05 (XML)

file 1, file 2

Solution

Exercise 1.05 - Lines Split

In the schema definition on line 165, the line has been split by tag.

Kudos if you noticed that there’s an extra attribute base, that the tag is no longer closed with /> but ends with a >, and that the name attribute is now ccy rather than Ccy

<xs:attribute 
	name="ccy" 
	type="CurrencyCode" 
	base="xs:string"
	use="required">

Exercise 1.06 (XML)

file 1, file 2

Solution

Exercise 1.06 - Lines Joined

In the schema definition, line 278 has been joined with line 279. Kudos if you noticed the spelling of elemnet, the absence of capitalisation in both pairs of maxoccurs and minoccurs, and at least one spellign error.

<xs:element name="ClrSysMmbId" type="ClearingSystemMemberIdentification3Choice" minoccurs="0" maxoccurs="1"/><xs:elemnet name="Nm" type="Max70Text" minocurrs="0" maxoccurs="1"/>

Exercise 1.07 (JSON)

file 1, file 2

Solution

Exercise 1.07 - data changed

On line 632, the value has an extra decimal place. Kudos if you noticed the small change in property name entryCustom4OCode.

"entryCustom4OCode": "20.000000000",

On 892, the cardTransactionReferenceNumber is "" rather than null.

"cardTransactionReferenceNumber": "",

Exercise 1.08 (JSON)

file 1, file 2

Solution

Exercise 1.08 - line added

Line 346 in the second file does not exist in the first file.

"nextPage": null

Kudos if you noticed that it is missing the trailing comma, making the JSON invalid.

Exercise 1.09 (JSON)

file 1, file 2

Solution

Exercise 1.09 - lines missing

Line 46-48 , 67-69, 126-128 and 298-300 in the first are missing in the second.

          "employeeCustom19Code": null,
          "employeeCustom20Code": null,
          "employeeCustom21Code": null,

          "employeeCustom19Value": null,
          "employeeCustom20Value": null,
          "employeeCustom21Value": null

          "reportCustom18Code": null,
          "reportCustom19Code": null,
          "reportCustom20Code": null,

          "allocationCustom18Code": null,
          "allocationCustom19Code": null,
          "allocationCustom20Code": null,

Kudos if you noticed that line 66 correctly omits the trailing comma, so the JSON is valid although the data is missing.

Kudos if you wondered why entryCustomCode has been left untouched.

Exercise 1.10 (JSON)

file 1, file 2, file 2b

Why have I given you two file 2s? Can you see any differences?

Solution

Exercise 1.10 - values changed, alternative formats

The second file has a new blank line at line 71

The second document status is marked "Pending" rather than "READY" on line 358

                "docStatus": "Pending"

Kudos if you wondered why Pending is not in upper case.

Kudos if you spotted that while file1 and file 2 have identical contents, they are rather different sizes. More kudos if you noticed their encoding is different.

-rw-r--r--@  1 james  staff   14617 10 Jan 11:14 transaction_4_a.json
-rw-r--r--@  1 james  staff   14628 10 Jan 11:25 transaction_4_b.json
-rw-r--r--@  1 james  staff   29254 10 Jan 11:25 transaction_4_b2.json

james@Mac diff tool exercise % file -I transaction_4_b.json 
transaction_4_b.json: text/plain; charset=utf-8
james@Mac diff tool exercise % file -I transaction_4_b2.json
transaction_4_b2.json: text/plain; charset=utf-16be

Your tool may not reveal this to you...

«JL: Add more, in CSV and TXT (i.e. dir list). »

Planned exercises include...

Exercises Group 2 – Code and config

Python, JavaScript, YAML/TOML, env

Exercises Group 3 – Markdown

Docs and readme.

Exercises Group 3 – Folders

Changed content, added / removed, renamed / moved, timestamp, permissions, ?encoding, ?os-specific metadata, ?hash,

Exercises Group 4 – Combos

sort / grep / filter – first, within git and across files for a commit, on directory / process lists, getting unique / count of changes,

This page is a work in progress. I'm sure that a curious reader can easily find my notes to myself. «JL: perhaps, if the script finds any notes, it can insert this message?»